What is the answer to this

Answer:
c=15
Step-by-step explanation:
This is a right triangle, so we can use the Pythagorean theorem to find the hypotenuse.
a^2 +b^2 =c^2
where a and b are the legs and c is the hypotenuse
9^2 +12^2 = c^2
81 +144 = c^2
225 = c^2
Take the square root of each side
sqrt(225) = sqrt(c^2)
15 = c