Calculate the second moment of area (also known as moment of inertia of plane area, area moment of inertia, or second area moment) and the section modulus of a profile with polygonal cross section and side length *A*. Use this to calculate deflection or stress in a loaded profile.

\( I_{yy}=\dfrac {5A^{4}\sqrt {3}} {16} \)

\( W_{yy}=\dfrac {5A^{3}\sqrt {3}} {16} \)