McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Trigonometry
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Exercise 28 Page 656

Determine the trigonometric ratio to use according to the given information and the unknown.

30.7

Practice makes perfect

We are given the length of one leg and the measure of an acute angle of a right triangle. We want to find the length of the hypotenuse.

Note that the given side is opposite the given angle, and the side we want to find is the hypotenuse. Therefore, we will use the sine ratio. sin θ = Length of leg opposite toθ/Length of hypotenuse In our triangle, we have that θ =21^(∘) and the length of the opposite leg is 11. We want to find the length of the hypotenuse.
sin θ = opposite/hypotenuse
sin 21^(∘) = 11/x
Solve for x
sin 21^(∘) * x = 11
x = 11/sin 21^(∘)
x=30.69470...
x≈ 30.7