The diameter of a cylinder is 28 cm and its height is 20 cm find the volume of the cylinder.

Given that, the diameter of the cylinder is 28 cm.

Then, the radius of the cylinder= $\frac{28}{2} \mathrm{cm}=14 \mathrm{cm}$

Height of the cylinder = h = 20cm

Then, the volume of the cylinder = ${\mathrm{\pi r}}^2\mathrm{h}=\frac{22}{7}\times 14\times 14\times 20=12320 {\mathrm{cm}}^3$