A student opens a 12.0 kg door If the door is 2.00 m in height and 1.00 m wide what is the moment of inertia of the door about its hinges. The equation for moment of inertia about the hinges is I =1/3 mr^2 should i use the the width or the height as my r i think it should be the width i am not 100% sure though.

Use the width, 1.00 in this case. "r" is the door's dimension perpendicular to the axis of rotation