Question

The doorsill of a campus building is h = 8 feet above ground level. To allow wheelchair access, the steps in front of the door are to be replaced by a straight ramp with constant slope 1/10, as shown in the figure. How long must the ramp be

Answer 1

every ten it goes up one so must be 80 feet

Answer 2

it said in the question that the answer is not 80 feet

Answer 3

Think in terms of drawing a triangle on a graph

y = 8

Your slope is 1/10. This means every time you move down one unit, you move to the right 10 units. By the time you reach y = 0, you will have reached x = 80.

So now use the Pythagorean Theorem -- a^2 + b^2 = c^2

where your "y" term is "a" (leg 1 of the triangle)
your "x" term is "b" (leg 2 of the triangle)
and "c" is the length of the ramp (the hypotenuse of the triangle)

(8)^2 + (80)^2 = c^2
6464 = c^2
80.4 = c