Answer:
b = 5
Step-by-step explanation:
We can use the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
12^2 + b^2 = 13^2
144+b^2 =169
Subtract 144 from each side
144-144+b^2 = 169-144
b^2 = 25
Take the square root on each side
sqrt(b^2) = sqrt(25)
b = 5
