Plot the vertices and and join them.
Obtain the equation of by using the formula of coordinate geometry
Equation of
And equation of is

The moment of inertia of the mass in about the axis is
Where is the density of the region
Here is proportional to the distance from - axis.
Assume . Then
Impose the limits on integrals.
Integrate the inner integral with respect to first.
Integrate with respect to .
Substitute the limits
[Simplify]
Thus, the moment of inertia about the axis is