With this calculator, you can calculate the length of a plate that runs diagonal to the bottom plate using the slope ratio and the length of the bottom plate.
Calculate the length of the diagonal plate on a gable wall using the bottom plate length and the slope ratio.
5: 12 slope ratio bottom plate length = 15' - 5" = 185 inches Calculate the slope factor from the slope ratio; To be able to do this, you need to know the formula that converts the slope ratio to a slope factor. Slope Factor Formula = √rise*rise+run*run/12 Plug in the values: √5*5+12*12/12 = 1.083333333. Multiply the bottom plate length by the slope factor to get the diagonal plate length; 185 *1.083333333 = 200.4166667 = 200 7/16 inches. The diagonal plate length is 200 7/16 inches or 16' - 8 7/16"