1. The problem statement, all variables and given/known data A uniform circular disk has radius 36 cm and mass 350 g and its center is at the origin. Then a circular hole of radius 7.2 cm is cut out of it. The center of the hole is a distance 10.8 cm from the center of the disk. Find the moment of inertia of the modified disk about the origin. 2. Relevant equations I=.25mr^2 (I think...!) 3. The attempt at a solution I tried finding the moment of inertia for both the hole and the disk and subtract the hole, but that didn't work. I'm not sure if that equation I posted is correct, I just googled it. How am I supposed to find the mass for the moment of inertia equation? At this point I just wish there was a straight up equation for it! Please help!