Question

If angles θ and α are complementary and sin θ = 3/4, what is cos α?

Answer 1

3/4

Explanation:

Since, angles θ and α are complementary.

Therefore,

θ + α = 90°

θ = 90° - α

Taking sin both sides.

sin θ = sin (90° - α)

sin θ = cos α (sin (90° - θ) = cos θ)

Since, sin θ = 3/4.....(given)

Hence, cos α = 3/4