Answer:
C
Step-by-step explanation:
using Pythagoras' identity in the right triangle
the square on the hypotenuse is equal to the sum of the squares on the other 2 sides , that is
x² = 40² + 9² = 1600 + 81 = 1681 ( take square root of both sides )
x = [tex]\sqrt{1681}[/tex] = 41
