Question

The total surface area of a solid cylinder is 231 cm and its curved surface area is 2/3 of the total surface area. Find the volume of the cylinder.

Answer 1

here is ur answer.....

Answer 2

the total surface area of cylinder =231cm^2

=> 2πr(r+h)=231 cm^2

=> 2πr^2+2πrh=231 cm^2--------(a)

its curved surface area is=2/3(231)cm^2 (given)

=> 2πrh=154 cm^2 --------(b)

putting value of 2πrh from equ. (b) in equ. (a) we get

=> 2πr^2+154=231

=>2πr^2=231-154

=>2πr^2=77

=>r^2=77/(2π)

=> r^2=12.25 (since π=22/7)

=> r=(12.25)1/2 cm = 3.5 cm

to find the value of h

now by putting the value of r=3.5cm in equ. (b) we get

=> 2πrh=154

=> 2(22/7)*3.5* h=154

=> 22h=154

=> h=154/22 cm = 7cm