A street in San Francisco has a 20% grade - 20 feet of rise for every 100 feet of
horizontal distance. What is the angle of elevation of the street?
Let
x ----> angle of elevation
we have that
tan(x)=20/100
tan(x)=1/5
x=tan^-1(1/5)=11.31 degrees
therefore
the angle of elevation is 11.31 degrees