Answer: 5
Step-by-step explanation:
a^2 + b^2 = c^2
12^2 + x^2 = 13^2
144 + x^2 = 169
x^2 = 25
square root both sides
x = 5
to check, do 12^2 + 5^2 =169
sqrt of 169 is 13
hope this helps
