Question 259665
The ramp forms a right triangle with legs 7 and 18. 
Find the length of the hypotenuse using the Pythagorean theorem,
{{{A^2+B^2=C^2}}}
{{{7^2+18^2=C^2}}}
{{{C^2=373}}}
{{{C=sqrt(373)}}} or approximately 19.3 feet.