State whether the following statement is true or false and justify: The volume of the frustum of a cone is \d…

State whether the following statement is true or false and justify: The volume of the frustum of a cone is $\frac{1}{3}\pi h[r_1^2+r_2^2-r_1{r}_2]$, where $h$ is the vertical height of the frustum and $r_1,r_2$ are the radii of the ends.