Question 260623
A right cylinder is formed from a rectangular sheet. Its volume is 
36/π cubic units. What is the rectangular sheet’s area? 
The rectangle's length is 4.


The volume of a right cylinder V = pi*r^2*h where r is the radius and  h height 

The length of the rectangle is given as 4.

That means the width forms the cicumference of the cylinder when the sheet is rolled.
Circumference = 2*pi*r

2 * pi* r = 4
r= 4/(2*pi)
r= 2/pi

V = pi*r^2*h 

insert the value of r in the above equation

V= pi*(2/pi)*(2/pi)* h    

36/pi = 4/(pi)^2  * h    Given that V= 36/pi

36*(pi)^2 / 4pi=  h

9pi = h          --h becomes the length of the sheet, L

Area of sheet = L * W
              = 9pi * 4
              = 36pi square units


M Ananth------------ mananth@hotmail.com