Answer:
Assuming the two sides are not the hypotenuse, then the third side would equal 5
Step-by-step explanation:
using the formula 
c is the hypotenuse while a and b are the sides.

so that simplifies to 9 + 16 = 
25=
in order to get just c alone, we must square both sides

this cancels out on the right side and leaves you with 5 on the left
therefore c=5