### Home > CC4 > Chapter 8 > Lesson 8.2.2 > Problem 8-113

8-113.

Use the angle relationships in the diagram below to determine the value of each variable. Name which geometric relationships you used. Homework Help ✎

Since the highlighted angles are vertical angles, and vertical angles are equal,

Use the Triangle Angle Sum Theorem to calculate .

To find , notice that it is the exterior angle in the small triangle that contains