% RECINERT(A,B,C,D) calculates the cross sectional moment of interia for
% a rectangular cross section
% A = outer width, B = outer height
% C = inner width, and D = inner height
%
% To evalute a filled rectangle set C and D = 0
%
%By Roger Cortesi (Course 2 Class of 1999) for 2.007
function [val] = recinert(a,b,c,d)

val = (a*b^3-c*d^3)/12;