So since this a right-angled triangle, you might want to use the Pythagorean Theorem. First, use the formula A(squared) + B(squared) + C(squared). Since c is unknown just put that as x(squared). Then, answer A(squared) and B(squared which would be 16mm and 12mm in this case. Multiply 16*16.... and you get 256. Then do the same to side B which is 12 and you get 144. Then know you can add them both together and get 400. What is the square root of 400? Yes, it’s 20. And there is you answer!
