Question

For what value of θ, in degrees, is sin θ = cos 58°?

Answer 1

Cofunction identities
sin (90° - Θ) = cos Θ
cos (90° - Θ) = sin Θ

Θ = 90° - 58°

Answer 2

Or you could take the arcsin.
\[\theta = \sin^{-1} (\cos 58°)\]