Question

What is the measure of ∠R?

Answer 1

∠ R ≈ 36.9

Explanation:

Using the cosine ratio in the right triangle

cosR =
`(adjacent)/(hypotenuse)` =
`(RT)/(RS)` =
`(8)/(10)` , then

∠ R =
`cos^(-1)` (
`(8)/(10)` ) ≈ 36.9 (to 1 dec. place )

Answer 2

Answers and Steps are in Pictures.