Given curves are $x^{2}=y$ and $y=4 x$
Intersection points are $(0,0)$ and $(4,16)$
$\therefore $ Required area $=\int \limits_{0}^{4}\left(4 x-x^{2}\right) d x$
$=\left[\frac{4 x^{2}}{2}-\frac{x^{3}}{3}\right]_{0}^{4} $
$=\left[32-\frac{64}{3}\right] $
$=\frac{32}{3} $ sq unit