Question

Can someone... figure this out?

Answer 1

see below

Explanation:

The angle with tangent a/b is the one at lower right. "a" is the side opposite that angle, and "b" is the side adjacent to it. The cosine of that angle will be the adjacent side divided by the hypotenuse:

cos(angle at lower right) =
`(b)/(√(a^2+b^2))`