A block is at rest on an inclined plane. The mass is 44 kg. µs = 0.54

Find the critical angle, θc, at which the
block just begins to slide.
Answer in units of ◦

force down the plane due to gravity

mg*sinTheta
force normal to the plane
mg*cosTheta
force up the plane due to friction.
mu*mgCosTheta

set them equal, I think you get
theta=arctan(mu)