Determine the trigonometric ratio to use according to the given information and the unknown.
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Practice makes perfect
We are given the length of two legs of a right triangle, and want to find the measure of one of its acute angles.
Note that we are given the opposite and the adjacent sides to the unknown angle. Therefore, to find its measure we will use the tangent ratio.
tan x = Length of leg opposite tox/Length of leg adjacent tox
In our triangle, we have that the length of the opposite and adjacent legs to x are 6 and 7, respectively.
The tangent of the angle is 67. Now, to isolate x we will use the inverse function of tan.
tan x=6/7 ⇔ x=tan ^(- 1)6/7
Let's use a calculator to find the value of tan ^(- 1) 67. 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 TAN, introduce the value 67, and press ENTER.
