Answer:
9
Step-by-step explanation:
The Pythagorean Theorem is a² + b² = c². c² is the hypotenuse while a² and b² are the legs.
So plugging it into the equation,
a² + 12² = 15²
a² + 144 = 225
a² = 81
a = 9
steps:
1. square the values
2. isolate the missing value
3. take the square root of both sides
