#### Question

A cylindrical bucket of diameter 28 cm and height 20 cm was full of sand. When the sand in the bucket was poured on the ground, the sand got converted into a shape of a cone. If the height of the cone was 14 cm, what was the base area of the cone ?

#### Solution

Radius of the bucket, *r* = \[\frac{28}{2}\]= 14 cm

Height of the bucket, *h* = 20 cm

Height of the cone, *H* = 14 cm

Let the radius of the base of the cone be *R* cm.

∴ Area of the base of the cone = \[\pi\]*R*^{2}

Now,

Volume of sand in the cone = Volume of sand in the cylindrical bucket

\[\therefore \frac{1}{3}\pi R^2 H = \pi r^2 h\]

\[ \Rightarrow \pi R^2 = \frac{3\pi r^2 h}{H}\]

\[ \Rightarrow \pi R^2 = \frac{3 \times \frac{22}{7} \times \left( 14 \right)^2 \times 20}{14}\]

\[ \Rightarrow \pi R^2 = 2640 {cm}^2\]

Thus, the base area of the cone is 2640 cm^{2}.