7-4: Trigonometry

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

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

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

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

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°)

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

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?

Find x 13 x 35°

Find x

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

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