As we know that, sin θ = (Opposite side / Hypotenuse) From Pythagoras’ theorem, (Hypotenuse)2 = (Adjacent side)2 + (Opposite side)2 ⇒ (5)2 = (Adjacent side)2 + (3)2 ⇒ Adjacent side = 4 As we know that, tan θ = (Opposite side / Adjacent side) ⇒ tan θ = (3/4) ⇒θ=tan−1(