The sine of the acute angle between the ground and the gradient is the ratio between the the gradient(hypotenuse) and the ramp height. Sine of the angle 30 is 0.5 so for a 30 degree angle you would need a one is to two ratio between the ramp height and gradient(hypotenuse).
cheers
PS.If the gradient is 60 inches and the height 30 inches the other side will be
51.961524227066318805823390245176 inches.
Best of luck
[This message has been edited by Sahir Shibley (edited August 26, 2001).]