Appendix E — Centroids and Area Moment of Inertia for Common Shapes

Centroid coordinates for common shapes
Shape \(\bar{x}\) \(\bar{y}\) Area
\(\frac{b}{3}\) \(\frac{h}{3}\) \(\frac{1}{2}bh\)
\(\frac{4r}{3\pi}\) \(\frac{4r}{3\pi}\) \(\frac{1}{4}\pi r^2\)
r \(\frac{4r}{3\pi}\) \(\frac{1}{2}\pi r^2\)
\(\frac{3}{4}b\) \(\frac{3}{10}h\) \(\frac{1}{3}ah\)
Area Moment of Inertia for common shapes
Shape Ix Iy

\(I_x=\frac{bh^3}{3}\)

\(\bar{I_{x'}}=\frac{bh^3}{12}\)

\(I_y=\frac{hb^3}{3}\)

\(\bar{I_{y'}}=\frac{hb^3}{12}\)

\(I_x=\frac{bh^3}{12}\)

\(\bar{I_{x'}}=\frac{bh^3}{36}\)

\(I_y=\frac{hb^3}{12}\)

\(\bar{I_{y'}}=\frac{hb^3}{36}\)

\(\bar{I_{x'}}=\frac{\pi r^4}{4}\) \(\bar{I_{y'}}=\frac{\pi r^4}{4}\)
\(I_x=\frac{\pi r^4}{8}\) \(I_y=\frac{\pi r^4}{8}\)