Respuesta :

Answer:

15.19 cm

Step-by-step explanation:

Pythagorean theorem
a^2 + b^2 = c^2
c = longest side
a^2 + 13^2 = 20^2
a^2 + 169 = 400
a^2 = 231, a = squareroot 231

Solution: x = 15.19 cm