Answer:
Explanation:
We are asked to find the measure of an angle given the triangle with 2 sides. This is a right triangle because of the small square representing a right angle. Therefore, we can use trigonometric functions. The three major functions are:
- sinθ= opposite/hypotenuse
- cosθ= adjacent/hypotenuse
- tanθ= opposite/adjacent
We are solving for angle R, and we have the sides TR (measures 9) and SR (measures 10).
- The side TR (9) is adjacent or next to angle R.
- The side SR (10) is the hypotenuse because it is opposite the right angle.
We have the adjacent side and the hypotenuse, so we will use the cosine function.
Since we are solving for an angle, we must take the inverse cosine of both sides.
If we round to the nearest tenth, the 4 in the hundredth place tells us to leave the 8 in the tenths place.
The measure of angle R is approximately 25.8 degrees and choice D is correct.