Answer:
36 units
Step-by-step explanation:
One leg of the triangle is 9 and the other is 12. Now you use the pythagorean theorem to solve for the last side of the the triangle. The pythagorean theorem is a^2+b^2=c^2. a and b are 9 and 12. It doesn't matter which order because of the commutative property. You know which ones are a and b because they are the shorter sides.
Now you plug it into the equation. 9^2+12^2=c^2. this simplifies to 81+144=c^2. Now you combine like terms and get c^2=225. You square root both sides now and get c=15. The longest side is 15. Now you add all of them together to find the perimeter. 9+12+15= 36
