Question

Find the volume, curved surface area and the total surface area of a cone having base radius $35cm$ and height $12cm$.

Answer 1

It is given that

Radius of the cone $=35cm$

Height of the cone $=12cm$

We know that

Volume of the cone $=\frac{1}{3}\pi r^{2}h$

By substituting the values

Volume of the cone $=\frac{1}{3}\times \frac{22}{7}\times {35}^2\times 12$

On further calculation

Volume of the cone $=15400c{m}^2$

We know that

Slant height $l=\sqrt{(r^2+h^2)}$

By substituting the values

$l=\sqrt{({35}^2+{12}^2)}$

On further calculation

$l=\sqrt{1369}$

So we get

$l=37cm$

We know that

Curved surface area of a cone $=\pi rl$

By substituting the values

Total surface area of cone $=\frac{22}{7}\times 35\times (37+35)$

On further calculation

Total surface area of cone $=22\times 5\times 72$

So we get

Total surface area of cone $=7920c{m}^2$