Moment of inertia of a square sheet about one side is I. Then the moment of inertia of the same square sheet about one of its diagonals is

(3)It  l  be  the  length  of each  side,  Then  I=13  ml2∴   Ix'=IAB− m.a22=13 ml2−14 ma2=112 ma2By  perpendicular  axis  theoremIo=Ixi + Iyj = 2IxAlso  Io=IAC+IBO=2IAC∴   IAC=Ix=112 mx2=112 ×  3I=14I.