1. A C M 5 2 4. If C = 20º, then cos C is equal to: A. sin 70 B. cos 70 C. tan 70

2. Skills Check

3. Using Trig to Find Missing Angles and Missing Sides

4. Finding a missing angle. Steps: 1) Where is the missing angle? 2) Identify the sides as H, O, or A 3) What Trig ratio is this? 4) Find the inverse trig function button on your calculator 5) Plug ratio in, hit enter

5. Ex: 1 Figure out which ratio to use. Find x. Round to the nearest tenth. 20 m 40 m Shrink yourself down and stand where the angle is. Identify the given sides as H, O, or A. x A O What trig ratio is this?

6. Ex: 2Figure out which ratio to use. Find x. Round to the nearest tenth. 15 m 50 m x Shrink yourself down and stand where the angle is. Identify the given sides as H, O, or A. H O What trig ratio is this?

7. Ex. 3: Find . Round to the nearest degree. 9 17.2 A O

8. Ex. 4: Find . Round to the nearest degree. 23 7 H A

9. Ex. 5: Find . Round to the nearest degree. 400 200 H O

10. Finding a missing side. Steps: 1) Identify the given angle 2) Identify the sides as H, O, or A 3) What Trig ratio is this? 4) Set ratio equal to trig angle then solve for x 5) Use sin,cos,tan button on calculator

11. Ex: 6Figure out which ratio to use. Find x. Round to the nearest tenth. 20 m x O A

12. Ex: 7 Find the missing side. Round to the nearest tenth. 80 ft x O A

13. Ex: 8 Find the missing side. Round to the nearest tenth. 283 m x H O

14. Ex: 9 Find the missing side. Round to the nearest tenth. 20 ft x A H

15. When we are trying to find a side we use sin, cos, or tan. When we are trying to find an angle we use ( INVERSE ) sin -1, cos -1, or tan -1.