Question

Let cosα = sinβ = 0.8957 and let 0° ≤ β ≤ 90°. If α = 26.4°, what is the value, in degrees, of angle β?

Answer 1

angle β = 63.6 degrees.
Sine and Cosine are co-functions so to find sin and cosine if they are between 0 and 90 degrees, subtract the cosine value from 90 to get the sine value and vice-versa.  90-26.4=63.6. you can check the work by plugging in sin 63.6 into the calculator to get the above answer of 0.8957.