# Physics help!

**URL:** <https://forum.kirupa.com/t/physics-help/251549>\
**Category:** Uncategorized\
**Created:** [February 10, 2008, 2:04am UTC](https://forum.kirupa.com/t/physics-help/251549 "2008-02-10T02:04:25Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![wo1olf](https://avatars.discourse-cdn.com/v4/letter/w/278dde/32.png) [@wo1olf](https://forum.kirupa.com/u/wo1olf)\
**Post date:** [February 10, 2008, 2:04am UTC](https://forum.kirupa.com/t/physics-help/251549/1 "2008-02-10T02:04:25Z")

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i have to calculate the moment of inertia about the z axis for a right triangle located in in the xy plan.  
The triangle has a mass of m, the base = a and the height is 2a. So the centroid has (a/3,2a/3)as coordinates.  
I’ve been looking for a formula for this but i didn’t find any. Does anyone knows how can i do it?