
Nathan B. answered 08/22/18
Tutor
5
(20)
Elementary and Algebraic skilled
|\
| \ r = ramp length
|7 \
---------
20
Since we have a right triangle and know two of the sides, we can use the Pythagorean theorem to solve this:
a2 + b2 = c2
72 + 202 = r2
I'll leave you to solve for r from here.