Topic: Angles E2.3 – Interior Angles of Triangles

Ontario Curriculum Expectation:

6.E2.3 use the properties of supplementary angles, complementary angles, opposite angles, and interior and exterior angles to solve for unknown angle measures.

Interior angles are the three angles inside a triangle.

The sum of the three interior angles is always 180º.

Finding the Unknown Angle

180° = a + b + c

180° = 70º + 85º + c

180° = 155º + c

c = 180° − 155º

c = 25º