1/12 is the maximum by law

Question

By law,the maximum slope of a wheelchair ramp is 1/12. A ramp is designed that is 4 feet high and has a horizontal length of 50 feet. Does this ramp meet the law? Explain. What could be adjusted on an unacceptable ramp so that it meets the law?

Answer 1

Raquel,

 

Slope is defined as rise (height) over run (length) so we can express this as slope = Height/Length.

 

Your rule says that the maximum slope (H/L) cannot exceed 1/12.  If the height is 4 this means the length must be at least 4(12) = 48.

 

In other words:  slope = H/L = 4(1)/4(12) = 4/48 = 1/12

 

If L is less than 48 the the slope is Greater than 1/12 and this is not allowed.  Any length longer than 48 and the slope is less than 1/12 and this is OK.

 

Since 50 > 48 the ramp will be acceptable.