C; 120 because 24x=360 so x=15. Then ABC is 8x, so 8*15=120.
The formula for finding the length is

All we have to do is plug in the numbers.

36 + 64 = 100
Since 100 =

we have to find the square root.

The length of the slide is 10 feet.
-0.03125 this would be the answer to that problem
Width would have to be a quadratic
Use long division to find the other factor of the cubic polynomial P (x).
P (x) factors in case it is reducible over R[x]
if it weren't then P (x) mod R [x] would be a field
otherwise you could use the Eisenstein Criterion.
V ≈ 603.18579in³ so i'd go with A.