Answer:
b = 24
explanation:
you use the Pythagorean theorem.
a^2 + b^2 =c^2
so we do 32^2 + x^2 = 40^2 then solve
32 squared is 1024 and 40 square is 1600 so you minus the 2 and get 576 then you square root 576 and you finally answer is 24
