Question

The measure of angle A to the nearest tenth of a degree is: A 18.5 B 19.5 C 20.5

Answer 1

Answer:

B

Step-by-step explanation:

This is a right triangle as shown by the right angle.

• The side opposite the right angle is the hypotenuse, which is 9.
• The side opposite angle A is 3.

So we have the opposite of A and the hypotenuse.

The trigonometric ratio that relates opposite side to hypotenuse is SINE.

$sin\theta=\frac{opposite}{hypotenuse}$

Since, we need angle A, $\theta$ is A, opposite side is 3, and hypotenuse is 9, we substitute:

$sinA=\frac{3}{9}\\sinA=\frac{1}{3}$

To solve for the angle, we use our calculator and find the inverse sin of $\frac{1}{3}$ :

$A=sin^{-1}(\frac{1}{3})\\A=19.47$

Rounding to nearest tenth of a degree:

$A=19.5$

B is the right choice.