1. Trig Ratios C 5 2 A M 4. If C = 20º, then cos C is equal to:
Be sure to discuss if C = 20, then sin C would equal ?
4. If C = 20º, then cos C is equal to:
A. sin 70 B. cos 70 C. tan 70

2. Skills Check

3. UNIT QUESTION: What patterns can I find in right triangles?
CCGPS Geometry
UNIT QUESTION: What patterns can I find in right triangles?
Standard: MCC9-12.G.SRT.6-8
Today’s Question:
How do we use trig ratios to find the missing sides and angles of a triangle?

4. Finding a missing angle
Finding a missing angle. (Figuring out which ratio to use and an inverse trig button.)

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

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

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

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

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

10. 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.