Unit 9 Contents

16. Find the missing degree measures in the triangles below. Do not measure the angles. Show or tell how you calculated the measure of each angle.

1. What is the measure of ∠A?
2. What is the measure of ∠AGB?
3. What is the measure of ∠AFC?
4. What is the measure of ∠EFC?
5. Look at polygon EFCD. What is the sum of all the angles?

Use the Add and Subtract Angles pages in the Student Activity Book to practice finding unknown angle measurements.

1. Which of these shapes are polygons?
2. Which are not polygons? Explain why each is not a polygon.