Question

A rocket has a cylindrical part which is converted into conical part at the front. The cylindrical part of the rocket radius is 12 cm and its height is 20 cm. The conical part of the rocket slant height is 4 cm and its radius is 7 cm. Find the surface area of rocket ( $\pi$ = 3)

• A. 1428 $c{m}^2$
• B. 1524 $c{m}^2$
• C. 1380 $c{m}^2$
• D. 1200 $c{m}^2$

Answer 1

The correct option is B 1524 $c{m}^2$

Surface area of rocket = CSA of cylindrical part + CSA of conical part
CSA of cylindrical part = $2\pi rh$
CSA of conical part = $\pi rl$
Surface area of rocket = $2\times 3\times 12\times 20+3\times 7\times 4$
= $1,440+84$
= 1524 $c{m}^2$