Answer:
60°
Explanation:
∠B is a right angle and all right angles are 90°, so if ∠B = 3*x then to find x you divid 3 by 90 to get x because 3*x = 90 once you do that you get 30 so x=30 then to find ∠C you just multiply 2 by 30 which gives you 60 which means the measure of ∠C = 60°
hope this helps :D