Volume of a Truncated Cone

A water tank is in the shape of a truncated cone (frustum). The radius of the top circular face is 4 meters, and the radius of the bottom circular face is 2 meters. The vertical height of the frustum is 6 meters. To find the volume of the frustum, we can use the formula:

$$ V = \frac{1}{3} \pi h (R^2 + Rr + r^2) $$

where $R$ is the radius of the top face, $r$ is the radius of the bottom face, and $h$ is the height. What is the volume of the water tank?