can a rectangular cantilever beam be a good simplification of a trapezoidal one ?

Question

can a rectangular cantilever beam be a good simplification of a trapezoidal one ?can a rectangular cantilever beam be a good simplification of a trapezoidal one ?

 

I'm analyzing a trapezoidal beam in which I need to get the moment of inertia so I thought that if I took the average of the longer and smaller sides I can get a close approximation.Is that reasonable? 

Answer 1

No please a rectangular uniform distribution loading on a cantilever beam cannot replace a trapezoidal variable loading. There are tables in the FE Civil Exam Handbook Page 111 that provides formulas for calculating Area moments of inertia for shapes such as trapezoids etc