Think of it like a triangle. You know SOH CAH TOA, right? We know the magnitude of the hypotenuse (the force of the force vector), and the magnitude of the adjacent side (the x component). You can use SOH CAH TOA to solve for the rest of the sides/angle.
cos(theta) = adjacent/hypotenuse
so cos(theta) = 73.5/85.0
so theta = cos-1(73.5/85.0) which i......
