Answer
$\pi$
Work Step by Step
We need to use the shell model as follows:
$V=\int_p^{q} (2 \pi) \cdot (\space radius \space of \space shell) ( height \space of \space Shell) \space dx$
$ \implies V= \int_0^{1} (2 \pi) \cdot (x)[\dfrac{3x}{2}] dx$
Now, $V= \pi \times \int_{0}^{1} [3x^2] dx$
or, $= \pi \times [x^3]_{0}^{1}$
or, $= \pi$