Question

In triangle PQR, angle P and R are complementary angles where cos P =(0.3) what is the measure in degrees of angle R round to the nearest tenth

Answer 1

`R = 17.5`

Explanation:

Given

P and R are complementary

`Cos\ P =0.3`

Required

Find the measure of R

`Cos\ P =0.3`

Take arccos of both sides

`P = cos^(-1)(0.3)`

`P = 72.5`

Since P and R are complementary, then:

`P + R = 90`

Make R the subject

`R = 90 - P`

Substitute values for P

`R = 90 - 72.5`

`R = 17.5`