Question

A rectangular piece of paper is 22 cm in length and 10 cm in width . It is rolled into a cylindrical along its length .find the surface area of this cylinder

Answer 1

Solutions

length of paper = Circumference = 22 cm

Width of paper = height of cylinder = 10 cm
Then,

Circumference of circle = 22 cm

=> 2πr = 22

=> 2x(22/7) x r = 22

=> r = 7/2 = 3.5 cm

Now,

Curved Surface Area of cylinder = 2πrh

= 2 x (22/7) x 3.5 x 10

= 220 cm²
Total surface area = 220 +2 x (22/7)x 3.5²

= 220 + 77

= 297 cm²

Thanks

Answer 2

Solutions :-

Let

length of paper = Circumference = 22 cm

Width of paper i.e height of cylinder = 10 cm
Then,

Circumference of circle = 22 cm.

=> 2πr = 22

=> 2x(22/7) x r = 22

=> r = 7/2 = 3.5 cm

Now,

We haveto find

Total surface area = 220 +2 x (22/7)x 3.5²

= 220 + 77

= 297 cm²

Good luck