Answer: 15 units
Explanation:
Since this is a right triangle, we will use the Pythagorean theorem. a and b are the legs, c id the hypotenuse. Here, we need to solve for the hypotenuse.
a² + b² = c²
9² + 12² = c²
81 + 144 = c²
225 = c²
= c
15 = c
15 units.