



 
Hi Bryan. The area of the cross section times the length of the road base will give you the volume needed. The cross section is a trapezoid (the top and bottom are parallel lines). The area of a trapezoid is (1/2)(h)(a+b) where h is the height between the parallel sides, and a and b are the lengths of the parallel You'll need to calculate the length of the bottom of the road base. To do that, remember that a 45 degree angle means that the length extensions (on each side), the slope and the depth form a right isosceles triangle, so the length extension is the same as the depth. Hope this helps. Keep your units straight! Stephen La Rocque  


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