QUOTE (GrilledSteezeSandwich @ Nov 21 2008, 10:39 AM)

a 78 percent pitch would work out to 37-38 degrees..any engineering people want to take a stab at this?? I don't have a scientiffic calculator.. I remember a 100 percent pitch equally to 45 degrees..
The pitch is the ratio of the height to the horizontal distance. I.E. your roof being a 5/12 pitch is 5" vertical rise vs a 12" horizontal run. The angle is the inverse arc tangent of that ratio. The pitch is a lot easier for the end result when you have to build it and you have rulers and levels, the angle is much better when you have to do the math of designing it.
At very small angles (less than 10 degrees) the pitch and angle are going to about equal each other, and as the angle increases the values diverge.
The 45 degree angle is a 100% pitch, meaning a 1:1 ratio of rise to run. A 50% pitch would be 1 foot rise for every 2 foot run, and the angle is arc tangent 0.5 = 26 degrees. It sounds a lot steeper as a 50% pitch but really, 26 degrees is pretty weak.
A 78 degree slope would be about a 500% pitch.