If cos B = 3/5 and (A + B) = 90°, find the value of sin A.

Question

Philoid · Accepted Answer

We are given that: cos B = 3/5

⇒ sin (90° – B) = 3/5

Since A + B = 90°, therefore A = 90° – B

Therefore, sin (90° – B) = sin A = 3/5