Moment of Inertia & Radius of Gyration

Figure shows triangular lamina which can rotate about different axes moment of inertia is maximum, about the axis
Show answer and solution
Answer: (c)
- is largest about the axis from which the mass lies farthest on average.
- and pass through the lamina, so mass lies close on both sides; (hypotenuse) has the shortest perpendicular height.
- About a leg, with the other leg. For , , the longer leg; for , , the shorter one.
- So is maximum about (c) QR.