Answer: 12
Step-by-step explanation: I assume you are talking about a triangle in which the Hypotenuse is 15 and leg A is 9
in this case we have to use a reverse pythagorean theorem
the original one is a^ + b^ = c^ then reverse it to get c^ - a ^ = b^
we know that C is 15 and A is 9 so substitute
15^ - 9^ = b^
15 ^ = 225 and 9^ = 81 so substitute again
225 - 81 = b^ then subtract
144 = b^ you know that the square root of 144 is 12 because 12 x 12 = 144
so 12 is the last side
hope this helps mark me brainliest if it did
