I need help with this problem. I try it out and got 39 but not 100% sure it right

Answer:
39 is correct
Step-by-step explanation:
Using Pythagoras' identity on the right triangle
c² = 36² + 15² = 1296 + 225 = 1521 ( square root both sides )
c = [tex]\sqrt{1521}[/tex] = 39