Question

The students of a Vidyalaya were asked to participate in a competition for making and
decorating penholders in the shape of a cylinder with a base, using cardboard. Each
penholder was to be of radius 3 cm and height 10.5 cm. The Vidyalaya was to supply
the competitors with cardboard. If there were 35 competitors, how much cardboard
was required to be bought for the competition?
​

Answer 1

Given:

• Radius of penholder, r = 3 cm
• Height of penholder, h = 10.5 cm

To find:

• How much cardboard was required to be bought for the competition?

Solution:

We know that,

Penholder has shape of cylindrical shape.

Cardboard required by 1 competitor = CSA of one penholder +Area of base

⇏ 2πrh + πr²

⇏ 2 × 22/7 × 3 + 10.5 + 22/7 + (3)²

⇏ 198 + 198/7

⇏ 1584/7 cm²

★ Cardboard required for 35 competitors,

⇏ 35 × 1584/7

⇏ 7920 cm²

Hence, 7920 cm² of cardboard was required to be bought for the competition.

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More to know:

• Curved Surface Area of cylinder = 2πrh

• Total surface area of cylinder = 2πr(r + h)

• Volume of cylinder = πr²h

Answer 2

Answer:

Answer

Given:

R=3cm, H=10.5cm

⇒Surface area = Curved Surface Area + Base Area

=2πrh+πr

2

=2×

7

22

×3×

10

10.5

+

7

22

×3×3cm

2

=198+

7

198

cm

2

=

7

1584

cm

2

⇒Area of cardboard sheet used by competitor =

7

1584

cm

2

⇒Area of cardboard sheet used by 35 competitors =

7

1584

×35

=7920cm

2