Question

Find the volume of the frustum cone whose base and top radius is $10$ cm and $2$ cm respectively. The height of the cone is $3$cm. (Use $\pi =\frac{22}{7}$).

• A. $369.36$ cm${}^3$
• B. $379.36$ cm${}^3$
• C. $389.36$ cm${}^3$
• D. $319.36$ cm${}^3$

Answer 1

The correct option is C $389.36$ cm${}^3$

Volume of frustum $=\frac{1}{3}\pi (R^2+r^2+Rr)\times h$

$=\frac{1}{3}\times \frac{22}{7}({10}^2+2^2+10\times 2)\times 3$

$=\frac{22}{7}(100+4+20)=\frac{22\times 124}{7}$

$=389.71$ ${cm}^3$