# Triangle Math

The sum of the internal angles that exist at the vertices always total the same number for every triangle — 180 degrees, or $\pi$ radians. What are its other angles? 3. For most shapes this lifestyle would be fulfilling. A right triangle has a 90° angle, while an oblique triangle has no 90° angle. Additionally, the Right Triangle Acute Angle Theorem states that the two non-right angles in a right triangle are acute; that is to say, the right angle is always the largest angle in a right triangle. All we need to figure out is the height. Abhinay Maths adda adda247 bank bankersadda bank exam banking bank po cat cgl cgpsc clerk continued fraction tricks dear sir decimal devesh. A triangle has three sides and is made of straight lines. Options include constructing triangles given three sides (SSS), two sides and the included angle (SAS), and two angles and an included side. 3 + 1 = 4, and 4 plus 1 = 5. 6) If the length of a side is a the area of the equilateral triangle is ¼a. Geometry Triangles. Used by over 7 million students, IXL provides personalized learning in more than 8,000 topics, covering math, language arts, science, social studies, and Spanish. Triangle Math is an app that permit to solve any kind of triangle. So, the measure of angle A + angle B + angle C = 180 degrees. Start studying geometry - triangles. See Similar Triangles SAS. What’s left is a right triangle. An acute triangle has all interior angles acute (less than 90°), a right triangle has one right angle (equal to 90°) and an obtuse triangle has one obtuse angle (greater than 90°). What did the altitude do to the base of the triangle? 6. Play Magic Triangle at Math Playground! Can you place the number discs in the correct positions?. If we assume that the square is a 1 x 1 unit, we can see that the base of the pink triangle is 1, the length of the square. The math worksheets are randomly and dynamically generated by our math worksheet generators. 20 is an A+. Its height is the length of segment BD. As you learned in the last lesson, a triangle is the simplest polygon, having three sides and three angles. Given the 30-60-90 triangle below, find the lengths of the missing sides: Since this is a 30-60-90 right triangle, we know that the sides exist in the proportion 1:sqrt(3):2. triangle top: right triangle bottom: equilateral triangle n. A triangle with altitudes 4; 5 and 6 cm is given. Triangle Facts for Kids. Scalene Triangle : A triangle with no two sides equal. Basic Trigonometric Ratios: Examples (page 1 of 2) Right triangles are nice and neat, with their side lengths obeying the Pythagorean Theorem. Classifying Triangles Using Their Angles Acute Triangle All angles are acute. "Trigonometry" is a branch of mathematics which deals with measuring the sides and angles in Right Angled Triangles. This activity will teach students how to find the area of a triangle. Filed under All math questions, Lines Angles and shapes, Upper Primary mathematics and tagged education, equilateral triangle, isosceles triangle, learning, mathematics question, polygon, primary school mathematics, right angle triangle, shapes, singapore math, singapore primary school math, upper primary | Leave a comment. What Are Some Geometry Formulas for Triangles? A triangle is a three-sided polygon where the sum of its interior angles equals 180 degrees. Start studying geometry - triangles. The triangle is the strongest shape due to the rigidity of its sides, which allows them to transfer force more evenly through their sides than other shapes. Triangle formulas with pictures and links to lessons on each one. The math worksheets are randomly and dynamically generated by our math worksheet generators. Solving problems related to plane geometry especially circles and triangles can be easily solved using a calculator. Mathematics goes beyond artithmetic with concepts like geometry, algebra, etc. A repository of tutorials and visualizations to help students learn Computer Science, Mathematics, Physics and Electrical Engineering basics. (from NCTM) Triangle Identification - Identify the type of triangle and angles. We are more than happy to answer any math specific question you may have about this problem. If all three sides of a triangle are of equal length, then it is called an equilateral triangle and all three of the interior angles must be 60 o, making it equilangular. More Math Fun. Select one of the links below to get started. Write answers in simplest radical form. 12 is a D-. In this session, you will build triangles and quadrilaterals to explore their properties. Congruent Triangles Classifying triangles Triangle angle sum The Exterior Angle Theorem Triangles and congruence SSS and SAS congruence ASA and AAS congruence SSS, SAS, ASA, and AAS congruences combined Right triangle congruence Isosceles and equilateral triangles. Acute triangles are better looking than all the other triangles. You can get help figuring out other things about right triangles, here. Lastly, if two triangles are known to be similar then the measures of the corresponding angle bisectors or the corresponding medians are proportional to the measures of the corresponding sides. We will look at several types of triangles in this lesson. In the example to the left, the triangle is drawn in black color. LOGIN New to Big Ideas Math? LOG IN. A repository of tutorials and visualizations to help students learn Computer Science, Mathematics, Physics and Electrical Engineering basics. Therefore, the two smaller triangles are 30-60-90 triangles. So, equiangular triangles are also called similar triangles. When a piece of lumber is added to a carpenter's square, it becomes a right triangle. Scalene Triangle : A triangle with no two sides equal. All of each may be of different or the same sizes; any two sides or angles may be of the same size; there may be one distinctive angle. Here are the things to remember. Pascal's triangle, in algebra, a triangular arrangement of numbers that gives the coefficients in the expansion of any binomial expression, such as (x + y)n. Are you confused while solving problems on Triangles, Circles & Construction Class 10? Visit Math Square and learn how to solve problems on Class 10 Triangles, Circles & Construction. How to use triangle in a sentence. Mathematics, Math Open Reference, or the National Library of Virtual Manipulatives, by searching for similar triangles applets. THEN they're ready for this puzzle just to see if they can piece things together. A right triangle is a triangle that has one angle. It is also useful to be able to calculate the area of a triangle from some of this information. The height of the triangle is shown in all cases, so trigonometry is not requited to answer the questions. Over 70 formulas included. 5 Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. The types of triangles classified by their sides are the following. This point is called the centroid of the triangle. Triangle Math and Science Academy located in Cary, North carolina - NC. One of the most interesting Number Patterns is Pascal's Triangle (named after Blaise Pascal, a famous French Mathematician and Philosopher). 2 Given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides. We will look at several types of triangles in this lesson. Mathematics GSE Geometry Unit 2: Similarity, Congruence, and Proofs July 2019 Page 5 of 188 Prove theorems involving similarity MGSE9-12. The above figure shows you an example of an altitude. One tip is hidden but no final solution is provided. In this lesson, students learn the Pythagorean Theorem, which states that the sum of the squares of the lengths of the legs of a right triangle is equal to the square of the length of the. The longer leg of the framing square is called the body and the shorter one leg is called the tongue. A breakout on the downside indicates the bears are winners. A right triangle is a triangle that has a 90 degree angle as one of its angles. Color the entries in Pascal’s triangle according to this remainder. The triangles are used in the examples below:. A Oblique Triangle is a triangle without any right angles. triangle [tri´ang-g'l] a three-cornered object, figure, or area, such as a delineated area on the surface of the body; called also trigone. The angles on this triangle are 22. In addition to the angles (A, B, C) and sides (a, b, c), one of the three heights of the triangle (h) is included by drawing the line segment from one of the triangle's vertices (in this case C) that is perpendicular to the opposite side of the triangle. 5) Every bisector is also an altitude and a median. SAS (side angle side) Two pairs of sides in the same proportion and the included angle equal. Can you get the numbers to add up to the same thing on three different sides of a triangle? Three games to play! 62. Take a look at a few similar triangles:. In a triangle, a median is a line joining a vertex with the mid-point of the opposite side. Find Triangle Math and Science Academy test scores, student-teacher ratio, parent reviews and teacher stats. How much space is inside a triangle? You can find out by calculating its area. If another triangle can be divided into two right triangles (see Triangle), then the area of the triangle may be able to be determined from the sum of the two constituent right triangles. The angles are NOT accurately measured! If this were the case then the worksheet would be useful in teaching pupils how to measure angles. It is one subject that becomes more practical for students as they progress, which is exciting for them! These worksheets have basic units from points, lines, segments, and area with a tool that allows the creation of customized worksheets. Explore math with desmos. 2 YIU: Introduction to Triangle Geometry 1. Types of triangles quiz. The figure shown below will be used for sides and angle notations. For example, triangle DEF is similar to triangle ABC as their three angles are equal. This will test your knowledge of proving triangles congruent, corresponding parts, isosceles triangles, medians, altitudes, and perpendicular bisectors. We discuss computations behind rendering objects in perspective. Lastly, if two triangles are known to be similar then the measures of the corresponding angle bisectors or the corresponding medians are proportional to the measures of the corresponding sides. We have different types of triangles. 0 users can upgrade for just $19 We gave Math Illustrations to the Minnesota State High School Mathematics League problem writing team to use on problems for the regular season and the state tournament. triangle [tri´ang-g'l] a three-cornered object, figure, or area, such as a delineated area on the surface of the body; called also trigone. A triangle is called a right triangle if one of its angles is a right angle, an acute triangle if all three angles are acute, and an obtuse triangle if it contains an obtuse angle. Notes about right triangles: The base b, height h and single right angle define the right triangle. We're an independent nonprofit that provides parents with in-depth school quality information. Two triangles are similar if: (a) 3 angles of one triangle are the same as 3 angles of the other triangle (b) 3 pairs of corresponding sides are in the same ratio (c) an angle of 1 triangle is the same as the angle of the other triangle and the sides containing these angles are in the same ratio. Proofs and Congruent Triangles - Glencoe. Area calculation of the triangle online. Triangle Math and Science Academy located in Cary, North carolina - NC. , Cary, NC 27511. It is named for the 17th-century French mathematician Blaise Pascal, but it is far older. Triangle formulas with pictures and links to lessons on each one. You will find addition lessons, worksheets, homework, and quizzes in each section. Triangles Triangle A triangle is a closed figure in a plane consisting of three segments called sides. The sum of the angles inside a triangle, exterior angles of triangles, equilateral triangles and isosceles triangles. Its height is the length of segment BD. Section B: Triangles. A triangle with altitudes 4; 5 and 6 cm is given. The following corollaries of equilateral triangles are a result of the Isosceles Triangle Theorem: (1) A triangle is equilateral if and only if it is equiangular. To fulfill its mission, TMSA implements a rigorous curriculum supported by research and with a strong emphasis on science, technology, engineering, and mathematics. The “metry” part of “Trigonometry” refers to the activity of measuring. Com provides free math worksheets for teachers, parents, students, and home schoolers. 12 videos Play all Math Antics Geometry Video Lessons mathantics; Order of Operations! (With. Find information related to equilateral triangles, isosceles triangles, scalene triangles, obtuse triangles, acute triangles, right angle triangles, the hypotenuse, angles of a triangle and more. If you want students to understand the triangle area formula, you might want to study parallelograms and rectangles first. Improve your math knowledge with free questions in "Classify triangles" and thousands of other math skills. Options include constructing triangles given three sides (SSS), two sides and the included angle (SAS), and two angles and an included side. IXL uses cookies to ensure that you get the best experience on our website. The bisector of an angle in a triangle separates the opposite side into two segments that have the same ratio as the other two sides:. Keep track of your score and try to do better each time you play. 312 Gregson Dr. Write answers in simplest radical form. Now, in geometry, you have a property of triangles called “similar triangles”. Geometry in high school lays the foundation for students so they can master concepts in higher math. For example, a scalene triangle (no sides the same length) can have one interior angle 90°, making it also a right triangle. A triangle has three sides and is made of straight lines. Types of Triangles by Length. Math Shape & Weight interactive teaching resources and activities to help your child with Maths. 0007 Now, we know that "perpendicular" means that it is going to form a right angle. A triangle or trigon is a two dimensional geometric object that has the specific qualities of having three straight sides that intersect at three vertices. A triangle with one right angle is right. Types of Triangles by Length. In this unit we will illustrate several formulae for. They're all free to watch! ↓. Scale ne Triangle. The angles are NOT accurately measured! If this were the case then the worksheet would be useful in teaching pupils how to measure angles. Geometry a three-sided polygon that can be classified by angle, as in an acute triangle, or by side, as in an equilateral triangle. A triangle is a geometric figure composed of three straight line segments that connect three separate points. A triangle has three angles. Browse all Geometry Problems. subtraction, multiplication and division. Triangle definition is - a polygon having three sides. 16 is a B-. Mathematics in Movies This is a collection of movie clips in which Mathematics appears. The longer leg of the framing square is called the body and the shorter one leg is called the tongue. We're an independent nonprofit that provides parents with in-depth school quality information. Since the sum of the angles in a triangle must be 180 o, this implies that the other two angles in a right triangle must add up to 90 o. The triangle is the general shape of geometry. ASA - known length of one side and two adjacent angles. Discuss findings as a whole group. triangle synonyms, triangle pronunciation, triangle translation, English dictionary definition of triangle. To build the triangle, start with "1" at the top, then continue placing numbers below it in a triangular pattern. ) P = a + b + c. For example, a scalene triangle (no sides the same length) can have one interior angle 90°, making it also a right triangle. In the series on the basic building blocks of geometry, after a overview of lines, rays and segments, this time we cover the types and properties of triangles. A right triangle has one angle of 16º. What did the altitude do to the base of the triangle? 6. In an isoceles triangle, the angle between the two equal sides can be more than, equal to, or less than 90 o. Given a triangle ABC , let the lines AO , BO and CO be drawn from the vertices to a common point O (not on one of the sides of ABC ), to meet opposite sides at D , E and F respectively. A special right triangle is a right triangle with some regular feature that makes calculations on the triangle easier, or for which simple formulas exist. The angle formed by one side of a triangle with the extension of another side is called an exterior angle of the triangle. Types of Triangles. Any point within the triangle can represent how the stick is broken into three pieces. Triangles can be classified according to the length of their sides and the size of their angles. Some special Pythagorean numbers: These are called Pythagorean triples. The sum of the three angles of a triangle is equal to 180 degrees. Triangles are plane shapes which lie in one plane. A triangle is a three-sided polygon that has three vertices, or corners. Download the Activity Sheet here. If all three sides of a triangle are of equal length, then it is called an equilateral triangle and all three of the interior angles must be 60 o, making it equilangular. Triangle Math and Science Academy, located in Cary, North Carolina, is committed to providing exceptional educational experiences with a STEM focus for students in grades K-12. Triangle Math and Science Academy located in Cary, North carolina - NC. In geometry it is shown that two triangles are congruent (i. If a triangle has two equal sides and one obtuse angle, we can call that triangle obtuse isosceles triangle. Uses Heron's formula and trigonometric functions to calculate area and other properties of given triangle. A right isosceles triangle will have a 90º angle and two 45º angles. The basic presumption in this chapter is that the reader has a firm grasp of decimals. If all three sides of a triangle are of equal length, then it is called an equilateral triangle and all three of the interior angles must be 60 o, making it equilangular. (This also follows from the Exterior Angle Theorem. com, a free online graphing calculator. yIf you’re finding the area of a right triangle, it doesn’t matter at what point in the formula you cut the rectangle in half—any of these variations will reach the same result: Area of a Triangle A = ½ B × H A = B × ½ H A = (B × H) ÷ 2 560. In the example to the left, the triangle is drawn in black color. A right triangle has one angle of 16º. Also geometry problems with detailed solutions on triangles, polygons, parallelograms, trapezoids, pyramids and cones are included. Congruent Triangles 4. Improve your math knowledge with free questions in "Classify triangles" and thousands of other math skills. But it is part of the sacred geometry none the less, for its energy conduction capacities. 2 Centers of similitude of two circles Considertwocircles O(R)andI(r), whosecenters O andI areatadistance d apart. Just enter at least 3 parameters (Triangle sides or angles) to get an automatic display of solved triangle and all calculated value! But there is more: the mathematic methods of calculation used to solve the triangle are visible by clicking on output parameters. A key concept in architecture is the use of triangles. Even better - sign up for an account to get full access to the thousands of interactive learning games inside What2Learn. Golden triangles are found in the nets of several stellations of dodecahedrons and icosahedrons. Theorems and Problems. Find here an unlimited supply worksheets for classifying triangles by their sides, angles, or both — one of the focus areas of 5th grade geometry. It welcomes anybody interested in the teaching profession, at any level, with an interest in learning and practicing the pedagogical approaches of math circles as they pertain to creative problem-solving. A triangle is determined by 3 of the 6 free values, with at least one side. Math test activities for students and teachers of all grade levels. 0 cm in length and the other. In an isoceles triangle, the angle between the two equal sides can be more than, equal to, or less than 90 o. WebMath is designed to help you solve your math problems. Its strong shape has been used to build buildings and bridges since the dawn of civilization. This will test your knowledge of proving triangles congruent, corresponding parts, isosceles triangles, medians, altitudes, and perpendicular bisectors. A triangle or trigon is a two dimensional geometric object that has the specific qualities of having three straight sides that intersect at three vertices. If someone asks you for a ‘height and base of a triangle’ there are three possible correct answers! (Depending on the shape and orientation of the triangle, however, one of these base/height pairs might be most obvious. Check yo u r an s wers. Triangle Math And Science Academy placed in the top 5% of all schools in North Carolina for overall test scores (math proficiency is top 5%, and reading proficiency is top 5%) for the 2015-16 school year. A triangle is a three-sided polygon. Altitude Index. Two triangles are similar if: (a) 3 angles of one triangle are the same as 3 angles of the other triangle (b) 3 pairs of corresponding sides are in the same ratio (c) an angle of 1 triangle is the same as the angle of the other triangle and the sides containing these angles are in the same ratio. Numbers that fit this pattern are called Pythagorean triples. Discuss findings as a whole group. Any two right triangles with the same two non-right angles are "similar", in the technical sense that their corresponding sides are in proportion. We will look at several types of triangles in this lesson. We have different types of triangles. Here is a collection of our printable worksheets for topic Triangles and Quadrilaterals of chapter Planes and Solids in section Geometry. The math worksheets are randomly and dynamically generated by our math worksheet generators. We have about 98 undergraduate mathematics majors and 41 minors. If you can do the math triangles, then you can do these math squares. Math & Science > Mathematics > Numbers and Formulas > Triangles ; Cite. Browse all Geometry Problems. If just two angles and one triangle are equal to two angles and another triangle, that's enough to establish that the two triangles are similar. We then describe vanishing points, answer how to measure distance in a receding direction in a perspective drawing and why a circle in three space. Let's take a look at some examples. Scalene Triangle A scalene triangle is a triangle that has three unequal sides, such as those illustrated above. Triangle (geometry) synonyms, Triangle (geometry) pronunciation, Triangle (geometry) translation, English dictionary definition of Triangle (geometry). 0000 This next lesson is on special segments within triangles. Perimeter Magic Triangles Perimeter Magic Triangles help children improve their addition skills using three addends! All you need are 6 milk caps labeled 1-6. A triangle with altitudes 4; 5 and 6 cm is given. What Are Some Geometry Formulas for Triangles? A triangle is a three-sided polygon where the sum of its interior angles equals 180 degrees. Acute Triangles. A triangle with all interior angles measuring less than 90° is an acute triangle or acute-angled triangle. None of the results herein will be proved, but it is a good exercise to try to prove them yourself. Numbers that fit this pattern are called Pythagorean triples. Tracing activities develop a child's control of the small muscles of the hands (fine motor skills) improving hand/eye coordination. The legs of the triangle form the angle and they are labeled and. Phone (919) 388-0077 | Fax (919) 651-1418. Proving Triangles Congruent We just started talking about congruent triangles in geometry. A right triangle has one right angle, and an obtuse triangle has one obtuse angle. Options include constructing triangles given three sides (SSS), two sides and the included angle (SAS), and two angles and an included side. Improve your math knowledge with free questions in "Classify triangles" and thousands of other math skills. LOGIN New to Big Ideas Math? LOG IN. Check yo u r an s wers. Pascal's triangle, in algebra, a triangular arrangement of numbers that gives the coefficients in the expansion of any binomial expression, such as (x + y)n. For example, a scalene triangle (no sides the same length) can have one interior angle 90°, making it also a right triangle. In 1816, while studying the Brocard points of a triangle, Crelle exclaimed, "It is indeed wonderful that so simple a figure as the triangle is so inexhaustible in properties. The right-angled triangle contains a right angle (an angle of 90˚). Special Right Triangles. A golden triangle, also known as the sublime triangle, is an isosceles triangle in which the duplicated side is in the golden ratio to the distinct side: = = +. In the Euclidean geometry three non collinear positions is the represented to the unique triangle and unique or the unique plane. What kinds of triangles are formed when you draw the altitude? 5. How to use triangle in a sentence. $\triangle ABC$ refers to a triangle with vertices A, B, and C (read as “triangle ay bee see”). 7 based on 35 Reviews "Urbana Catering is rolling out its new. Equilateral triangles are triangles in which all three sides are the same length. Congruent triangles are triangles that are identical to each other, having three equal sides and three equal angles. Triangle definition is - a polygon having three sides. In this unit we will illustrate several formulae for. About the PoW Library. What does "equilateral" mean? It simply means that all three sides of the triangle are the same length. Improve your math knowledge with free questions in "Triangles" and thousands of other math skills. Pascal's Triangle. Improve your math knowledge with free questions in "Classify triangles" and thousands of other math skills. The sum of the internal angles that exist at the vertices always total the same number for every triangle — 180 degrees, or$ \pi \$ radians. Triangles are polygons. Rather, the worksheet is designed to teach pupils that the internal angles of a triangle equal 180 degrees, and how to use that knowledge to find a missing angle. It's not hard to prove that two triangles is similar using their angles. A right triangle has one right angle. 4 Isosceles and Equailateral Triangles 4. Infinite Geometry covers all typical Geometry material, beginning with a review of important Algebra 1 concepts and going through transformations. Sometimes it is specified as having two and only two sides of equal length, and sometimes as having at least two sides of equal length, the latter version thus including the equilateral triangle as a special case. The Triangle Math Teachers’ Circle is an initiative hosted by the Department of Mathematics at North Carolina State University. If you know special triangle property use calculator for an equilateral, isosceles or right triangle. SEE ALSO: Acute Triangle , Equilateral Triangle , Isosceles Triangle , Obtuse Triangle , Triangle. Geometry Facts and Calculations. Abhinay Maths adda adda247 bank bankersadda bank exam banking bank po cat cgl cgpsc clerk continued fraction tricks dear sir decimal devesh. In this Early Edge video lesson, you'll learn more about Equilateral, Isoceles and Scalene Triangles, so you can be successful when you take on high-school Math & Geometry. com, a free online graphing calculator. The following corollaries of equilateral triangles are a result of the Isosceles Triangle Theorem: (1) A triangle is equilateral if and only if it is equiangular. According to Business Insider's quant reporter Andy Kiersz, the key to solving the problem is the height of the pink triangle. We touch upon the geometry of similar triangles, rigid motions in three space, perspective transformations, and projective geometry. Theorems and Problems. The legs of the triangle form the angle and they are labeled and. 4 Prove theorems about triangles. SSS is more formally known as the Side-Side-Side Triangle Congruence Theorem (or maybe Edge-Edge-Edge Triangle Congruence Theorem). Each assessment provides you with an instant feedback and an overall score. 7 based on 35 Reviews "Urbana Catering is rolling out its new. A triangle may be classified by how many of its sides are of equal length. Right triangles If the legs of a right triangle have the same length, then the angles opposite those legs have the same measure. Encyclopædia Britannica, Inc. Perimeter Magic Triangles Perimeter Magic Triangles help children improve their addition skills using three addends! All you need are 6 milk caps labeled 1-6. Color the entries in Pascal’s triangle according to this remainder. Any point within the triangle can represent how the stick is broken into three pieces. 4 Triangles and Angle Bisectors. Find Triangle Math and Science Academy test scores, student-teacher ratio, parent reviews and teacher stats. Triangle Math and Science Academy, located in Cary, North Carolina, is committed to providing exceptional educational experiences with a STEM focus for students in grades K-12. The pyramidal form, while not one of the so called platonic solids, as is a only half an Octahedron and not solid. Filed under All math questions, Lines Angles and shapes, Upper Primary mathematics and tagged education, equilateral triangle, isosceles triangle, learning, mathematics question, polygon, primary school mathematics, right angle triangle, shapes, singapore math, singapore primary school math, upper primary | Leave a comment. 3 Triangle Congruence by ASA and AAS 4. He becomes many different shapes until at last he he misses his friends and learns that it's not so bad being a triangle!. com FREE DELIVERY and Returns possible on eligible purchases. A triangle with vertices , , and is denoted. from plane Euclidean geometry that are most useful in math contests where the goal is computational results rather than proofs of theorems. Fact Families are sets of three numbers that can be divided or multiplied together and they help develop the understanding of the relationship between multiplication and division. Math & Science > Mathematics > Numbers and Formulas > Triangles ; Cite. If all three sides of a triangle are of equal length, then it is called an equilateral triangle and all three of the interior angles must be 60 o, making it equilangular. Mathematical background. Adjust the angles in the triangle by dragging the endpoints along the circles. That being said, you still want to get those questions right, so you should be prepared to know every kind of triangle: right triangles, isosceles triangles, isosceles right triangles—the SAT could test you on any one of them. 2 Triangle Conguence by SSS and SAS 4. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere. The angle formed by one side of a triangle with the extension of another side is called an exterior angle of the triangle.