Can someone help me? Thanks! ;D

Answer:
13
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 = 5² + 12² = 25 + 144 = 169 ( take the square root of both sides )
x = [tex]\sqrt{169}[/tex] = 13