Question

What is the measure of ∠R?

Answer 1

∠ R ≈ 36.9°

Explanation:

using the cosine ratio in the right triangle.

cos R =
`(adjacent)/(hypotenuse)` =
`(RT)/(RS)` =
`(8)/(10)` = 0.8 , then

∠ R =
`cos^(-1)` (0.8 ) ≈ 36.9° ( to 1 decimal place )