1. 4.3 Right Triangle Trigonometry
Students will evaluate trigonometric functions of acute angles.
Students will use the fundamental trigonometric identities.
Students will use a calculator to evaluate trigonometric functions.
Students will use trigonometric functions to model and solve real-life problems.

2. SOHCAHTOA

5. p. 274 #9
Sketch a right triangle corresponding to the trigonometric function of the acute angle .

6. p. 274 #16
Sketch a right triangle corresponding to the trigonometric function of the acute angle .

7. p. 274 #17 Construct an appropriate triangle to complete the table.
Function (deg) (rad) Function Value
sin _____ _______

8. Trigonometric Values of Common Anglesx y
(0, 1)
90°
120°
60°
135°
45°
30°
150°
(–1, 0)
180°
(1, 0) 0°
360°
210°
330°
315°
225°
240°
300°
(0, –1)
270°
Trigonometric Values of Common Angles

9. p. 275 #22 Construct an appropriate triangle to complete the table.
Function (deg) (rad) Function Value
csc ______ _____

10. p. 275 #29
Use the given function values to find the indicated trigonometric functions. a. b. c. d.

11. Section 4.3, Fundamental Trigonometric Identities, pg. 270

12. Use the trigonometric identities to transform one side of the equation into the other.
p. 275 #33

13. Use the trigonometric identities to transform one side of the equation into the other.
p. 275 #35

14. Use the trigonometric identities to transform one side of the equation into the other.
p. 275 #37

15. Use the trigonometric identities to transform one side of the equation into the other.
p. 275 #39

16. Use a calculator to evaluate the trigonometric function
Use a calculator to evaluate the trigonometric function. Round to four decimal places.
p. 275 #43
a b.

17. Find each value in degrees and radians by using your unit circle.
p. 275 #47
a b.

18. p.276 #57
A six-foot person walks from the base of a streetlight directly toward the tip of the shadow cast by the streetlight. When the person is 16 feet from the streetlight and 5 feet from the tip of the streetlight’s shadow, the person’s shadow starts to appear beyond the streetlight’s shadow.
Draw a right triangle that gives a visual representation of the problem. Show the known quantities of the triangle and use a variable to indicate the height of the streetlight.
Use a trigonometric function to write an equation involving the unknown quantity.
What is the height of the streetlight? :