1. 7-4: Trigonometry

2. hypotenuse
opposite side θ
adjacent side
***With angles we often use θ as our variable instead of x.

3. Trigonometric Ratios Words Symbol Definition sine θ sin θ opposite
hypotenuse
cosine θ
cos θ
adjacent
tangent θ
tan θ

4. To help you remember Some Old Hippie Caught A High Trippin’ On Acid
Sine – opposite/hypotenuse
Cosine – adjacent/hypotenuse
Tangent – opposite/adjacent

5. Find sine, cosine and tangent for each picture.θ 9 8 θ 12 5

6. Finding trig ratios using the calculator:
Make sure your calculator is in degree mode.
Type it in
EX1: Find sin(33°) EX2: Find tan(22°)

7. angle of elevation—from your line of sight up.
angle of depression—from your line of sight down.
Angle of Elevation
Line of sight
Angle of Depression

8. Real-Life Examples
Sam and Vincent want to measure the height of the C building at Elkin High School, so they stand 20 ft. away from the base of the building and use a clinometer 5 ft off the ground to find that the angle of elevation to the top of the building is 65°. What is the height of the building?

9. Find x 13 x
35°

10. Find x

12. Assignment 7.4 Regular p. 368-369 22-36, 43, 45-47, 49-51
Honors p , 43, 45-47, 49-51, 56-58

13. Assignment
p. 368; 43, 45-47, 57
and
Worksheet 4-9