Answer:
the ten-inch side is the hypotenuse.
Explanation:

a= 6
b= 8
c= 10
use substitution to replace the variables in the equation, it should look like this:
36+64=100
the equation above is true, so the answer is that the 10-inch side is the hypotenuse.
*** I couldn't make a diagram on here, so I explained the math. hope this helps