Question

Question 13
The radii of the top and bottom of a bucket of slant height 45 cm are 28 cm and 7 cm, respectively. The curved surface area of the bucket is

(A) $4950c{m}^2$
(B) $4951c{m}^2$
(C) $4952c{m}^2$
(D) $4953m^2$

Answer 1

Option (A) is correct.
Given, the radius of the top of the bucket , R = 28 cm
And the radius of the bottom of the bucket, r = 7cm
Slant height of the bucket , l = 45 cm.
Since, bucket is in the form of frustum of a cone.
$\therefore$ Curved surface area of the bucket $=\pi l[R+r]=\pi \times 45(28+7)$
$[\because Curvedsurfaceareaoffrustumofacone=\pi (R+r\left)l\right]$
$=\pi \times 45\times 35=\frac{22}{7}\times 45\times 35=4950c{m}^2$