Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
Mid-Chapter Quiz
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Exercise 20 Page 514

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

34.8

Practice makes perfect

We are given the length of one leg and a hypotenuse of a right triangle, and want to find the measure of one of its acute angles.

Note that we are given the opposite side to the unknown angle and a hypotenuse. Therefore, to find its measure we will use the sine ratio. sin x = Length of leg opposite tox/Length of hypotenuse In our triangle, we have that the length of the opposite leg to x and hypotenuse are 4 and 7.
sin x = Opposite/Hypotenuse
sin x = 4/7
The sine of the angle is 47. Now, to isolate x we will use the inverse function of sin. sin x=4/7 ⇔ x=sin ^(- 1)4/7 Let's use a calculator to find the value of sin ^(- 1) 47. First, we will set our calculator into degree mode. To do so, push MODE, select Degree instead of Radian in the third row, and push ENTER. Next, we push 2ND followed by SIN, introduce the value 47, and press ENTER.

The value of x is about 34.8.