Class 11 NEET Physics System of Particles and Rotational Motion

Moment of inertia of uniform circular disc about diameter =I
According to theorem of perpendicular axes.
Moment of inertia of disc about axis =2I=

1

2

mr2
Applying theorem of parallel axes
Moment of inertia of disc about the given axis=2I+mr2=2I+4I=6I