Answer:
x = 25
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse x is equal to the sum of the squares on the other two sides, that is
x² = 20² + 15² = 400 + 225 = 625 ( take the square root of both sides )
x = [tex]\sqrt{625}[/tex] = 25
