Octagonal Cross Section with Parabolically Increasing "Span" Hi all, could some one tell me what I am doing wrong in my analysis in the attached file? Its a parabolical flare column with an octagonal cross section. The effect of the parabolic flare simply stretches the octagon so that the problem can be reduced to rectangle with parabolic increasing length with a constant height with an added term which adds the edge areas for each unit length. I feel confident in my analysis but it's giving me incorrect answers. I keep checking over and over and can't find an issue with my analysis. When I plug in test values in my final formula, I get 50.7 cubic yards but I know for sure that the answer is 35.7 cubic yards. In the attached files here are the variable values that I am using: b=5.5 ft s=11 ft p=16.5 ft l= 12 ft A=-2.5 B=26.625 C=-54.313 I really cannot see the error. If anyone can help with this it'd be much appreciated.