Help me please and thank you

Step-by-step explanation:
The PYTHAGOTREAN theorem for RIGHT triangles states
Hypotenuse^2 = Leg1 ^2 + Leg2 ^2
For THIS right triangle:
x^2 = 8^2 + 13^2
x^2 = 64 + 169
x^2 = 233
x = sqrt (233) = 15.2643 units <===round as requested in your work