Unit 5 Section 6 : Finding Angles in Triangles
Sum of the Interior Angles of a Triangle
The angles inside a triangle are called interior angles.
The three interior angles in a triangle will always add up to 180°.
At each corner the exterior and interior angles are on a straight line, so at each corner these two angles add up to 180°.
Types of Triangle
When looking at the sides, there are three types of triangle: Isosceles, Equilateral and Scalene
Example QuestionWork out the answer to the question then click on the button marked to see whether you are correct.
Look at the triangle in the diagram below.
ExercisesWork out the answers to the questions below and fill in the boxes. Click on the button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on to see the answer.
Produced by A.J. Reynolds April 2011