Question

A right cylinder has a circumference of 9π cm. Its height is twice the radius. Identify the lateral area and the surface area of the cylinder.

L = 264.6 cm2 ; S = 346.2 cm2
L = 81 cm2 ; S = 121.5 cm2
L = 254.5 cm2 ; S = 381.7 cm2
L = 188.5 cm2 ; S = 326.4 cm2

Answer 1

we have given that circumference of a right cylinder.

`C=2\pi r=9\pi ,r=9/2cm`

where the base in circular.

`h=2r,h=2*9/2=9cm`

we know that surface area
`=2\pi rh=2*\pi *9/2*9=81\pi ,cm^2`=
`254.5cm^2`

surface area=
`2\pi rh+2\pi r^2=81\pi +9\pi *(9/2)=381.7cm^2`.