Respuesta :

Answer:

51°

Step-by-step explanation:

Reference angle (θ) = ?

Opposite side length = 31

Hypotenuse length = 40

Apply SOH, which is;

Sin θ = Opp/Hyp

Plug in the values

Sin θ = 31/40

θ = sin^{-1}(31/40)

θ = 51° (neatest whole degree)