Last Updated on July 28, 2026 by Maged kamel
Video for Ixy for a triangle.
How do we get the expression for the Product of inertia for a triangle at the external left corner and at the CG? We use the previously estimated data for Ixy values for the two right angles. By using the two formulas for Ixy for both right-angle cases 1 and 2
We add these values to obtain the final Ixy for the triangle, which equals 1/12(2a + b) h. The distance a is the distance from the left corner to the point d, where b is the base distance of the triangle, while H is the triangle height.
To get the product of inertia Ixy at the Cg, we subtract the product of area by (1/3h)*(1/3(a+b)) from the estimated Ixy value. We get Ixy Cg = bh^2 (2a-b)/72.
The Timestamps for the video are shown.
The previous video, No. 20, is for Iy at the Cg for a triangle.
The related post is post-15-Product of inertia Ixy for the triangle.
The next video is for Ix and Iy for an isosceles triangle.
There is a valuable resource: a calculator to estimate the moment of inertia for variable shapes.