Respuesta :

Answer:

A

Step-by-step explanation:

You have to use Pythagorean theorem.

a^2 + b^2 = c^2

x^2 + 3^2 = 5^2 (you know that b=3 because is the half of 6)

x^2 + 9 = 25

x^2 = 25 - 9

x^2 = 16

x = √16

x = 4