A wooden stool is in the form of a frustum of a cone with slant edge 40cm,top diameter 30cm and bottom diameter 50cm.

- calculate the perpendicular height of the stool
- calculate the total surface area of the stool in terms of π
- calculate the volume of wood used to make the stool in terms of
- given that the density of the wood used to make the stool is 0.8g/cm
^{3}, calculate the mass of the stool in kg