Question

Mohan lives in Hyderabad in Telengana. Those were very hot days of May. He thought that if we

human beings need so much water to drink, wont the birds also be thirsty. He decided to

prepare a vessel to provide water for birds. He found a flexible blue coloured plastic rectangular

sheet 41cm x 15cm. He rolled it along its length and joined the opposite ends using a tape. He

wanted to have a circular base for this cylinder and searched for another cylinder. He found a

square sheet 15cm x 15cm. He cut a circular sheet just equal to the base of the cylinder from it.

Now answer the following questions:

a) The curved surface area of the cylinder formed is:

i. 540 cm2

ii. 560 cm2

iii. 640 cm2

iv. 660 cm2

b) The radius of the base of the cylinder is:

i. 2 cm

ii. 3.5 cm

iii. 7 cm

iv. 10 cm

c) The radius of the circular base required for cylinder is

i. 154 cm

ii. 216 cm

iii. 260 cm

iv. 308 cm

d) How much will be the area of square sheet left unused after removing the circular base of

the cylinder from it?

i. 69 cm2

ii. 71 cm2

iii. 83 cm2

iv. 91 cm2​​

Answer 1

The curved surface area of the cylinder formed is:

Answer = The radius 'r' of a cylinder is the radius of its base. Now, the area of the rectangle = length × breadth. 2πr is the circumference of the circle and h is the height. Area of the curved surface will be = 2πr × h = 2πrh.

b) The radius of the base of the cylinder is:

answer= 2 cm

The radius of the circular base required for cylinder is

answer=Given volume and lateral area: r = 2 * V / A_l , Given base area: r = √(A_b / (2 * π)) , Given lateral area and total area: r = √((A - A_l) / (2 * π)) .

How much will be the area of square sheet left unused after removing the circular base of

the cylinder from it?

answer = 83

Answer 2

Answer:

a) The curved surface area of the cylinder formed is:

iii. 640 cm2

b) The radius of the base of the cylinder is:

i. 2 cm

c) The radius of the circular base required for cylinder is

iii. 260

d) How much will be the area of square sheet left unused after removing the circular base of the cylinder from it?

i. 69 cm2