Question

The curved surface area of the frustum cone shaped bucket is $360\pi c{m}^2$. The top and bottom diameter of the bucket is $6$cm and $12$ cm. What is the slant height?

• A. $10$ cm
• B. $20$ cm
• C. $30$ cm
• D. $40$ cm

Answer 1

Answer: (D)

$40$ cm

Radius $=\frac{\text{diameter}}{2}$

$D=12,d=6$
$R=6,r=3$

Curved surface area $=\pi (R+r)s$
$360\pi =\pi (6+3)\times s$

$s=\frac{360}{9}$

$s=40$ cm