Answer:
12
Step-by-step explanation:
Since this is a right triangle ,we can use the Pythagorean theorem
a^2+b^2 = c^2
a^2 + 5^2 = 13^2
a^2 +25 = 169
Subtract 25 from each side
a^2 = 169-25
a^2 = 144
Taking the square root of each side
sqrt(a^2) =sqrt(144)
a = 12
