e1 = 20.714285714285715;
e2 = 11.785714285714286;
d = 20;
H = 30;
t = 15;
b = 30;

Iyz = d*H  * ( e1 - d/2) * ( e2 - H/2) + b*t * (e2 - t/2) * (e1 - d - b/2);