Question

A rocket is in the form of a circular cylinder closed at the lower end and a cone of the same radius is attached to the top. The radius of the cylinder is 2.5 m, its height is 21 m and the slant height of the cone is 8 m. Calculate the total surface area of the rocket.

Answer 1

Radius of the cylinder = 2.5 m
Height of the cylinder = 21 m 

Curved surface area of the cylinder `= 2pirh = 2xx22/7xx2.5xx21=330` m²

Radius of the cone = 2.5 m

Slant height of the cone = 8 m

Curved surface area of the cone `= pirl = 22/7 xx2.5xx8 = 62.86` m²

Area of circular base = `pir^2 = 22/7xx2.5xx2.5xx=19.643`

∴ Total surface area of rocket = 330 + 62.86 + 19.643 m²