Angles in Isosceles Triangles WORKSHEET

This worksheet on Angles in Isosceles Triangles is designed to develop students’ understanding of angle properties through a progression of reasoning and problem-solving tasks.

In Section A, students explore the property that base angles in an isosceles triangle are equal through a discovery activity, using the fact that angles in a triangle sum to 180°.

Section B builds on this by using examples and non-examples. Learners are prompted to identify pairs of equal angles and determine whether specific angles are equal within a range of isosceles triangle diagrams.

In Section C, students calculate missing angles in a series of increasingly challenging questions. They will work out fifteen angles in total, applying their understanding of isosceles triangles as well as other angle rules, such as angles on a straight line and angles around a point.