Page 813 - Algebra 1

798 Saxon Algebra 1
Example 2 Using a Calculator with Trigonometric Ratios
a. If ∠A = 42°, find sin A, cos A, and tan A to the nearest ten-thousandth. SOLUTION
Use a calculator to find the value of the trigonometric ratios.
42 sin A ≈ 0.6691 42 cos A ≈ 0.7431 42 tan A ≈ 0.9004
b. If ∠A = 33°, find csc A, sec A, and cot A to the nearest ten-thousandth. SOLUTION
Use a calculator.
33 OR133 csc A ≈ 1.8361
33 OR133 sec A ≈ 1.1924
33 OR133 cot A ≈ 1.5399
Example 3 Using Trigonometry to Find Missing Side Lengths Use a calculator to find trigonometric ratio values.
a. Find the value of x. Round to the nearest hundredth.
SOLUTION
Since the missing side is opposite the angle and the adjacent side length is given, use the tangent ratio.
t a n 2 8 ° = _x 9
9 · tan 28° = x 4.79 ≈ x
b. Find the value of x and y. Round to the nearest hundredth.
x
SOLUTION _ _ sin A = opposite leg
cos A = adjacent leg _ _
hypotenuse
_y 12
B
x
C
12
hypotenuse
_x 12
12 · sin 52° = x 9.46 ≈ x
y
52° A
sin 52° =
cos 52° =
12 · cos 52° = y 7.39 ≈ y
9
28°