What acute angle (theta) satisfies the equation sin(theta) = cos (2(theta) + 60degrees)?

Question

find an acute angle (theta) that satisfies the equation sin(theta) = cos (2(theta) + 60°)

Answer 1

sinθ=cos(2θ+60)

sinθ = cos (90-x ) ------------trigonometric idendity

cos(90-θ) = cos (2θ+60)

90 -θ = 2θ+60

3θ = 30

θ = 10