Question

In a SUPW class, 20 student made pen stand of cupboard. the base of the pen stand is a circle with radius 3.5 cm and height of the pen stand is 10.5 cm .find how much cupboard was used by each. how much glazed paper is used on its outer surface also find the total cupboard and glazed paper used by the whole class .​

Answer 1

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No. of students in the SUPW class = 20

The radius of the base of the pen stand, r = 3.5 cm

The height of the pen stand, h = 10.5 cm

Thus,

Total cardboard required to make one pen stand is given by,

= [CSA of a cylinder] + [CSA of base of pen stand]

= [2πrh] + [πr²]

= πr [2h + r]

= (22/7) * 3.5 * [(2*10.5) + 3.5]

= (22/7) * 3.5 * 24.5

= 269.5 cm²

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Thus,

Glazed paper used on the outer curved surface of the pen stand (neglecting the base area) is given by,

= [Cardboard required to make one pen stand] – [Area of the base of the pen stand]

= 269.5 – [π²]

= 269.5 – [(22/7) * (3.5)²]

= 269.5 – 38.5

= 231 cm²

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= 20 * [(Total cardboard used for each pen stand) + (Total glazed paper used on the outer curved surface of each pen stand)]

= 20 * [269.5 + 231]

= 20 * 500.5

= 10010 cm²

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Answer 2

Answer:

Total cardboard used for one pen stand:

Radius = 3.5 cm

Height = 10.5 cm

=> TSA = Curved Surface Area of cylinder + area of circle

=> TSA = $\tt{2 \pi rh + \pi r^{2}}$

=> TSA = 11 × 24.5

=> Total surface area = 269.5 sq cm

Glazed paper used for curved surface area:

=> CSA = $\tt{2 \pi r h}$

=> CSA = 231 sq cm

Total paper used by class:

20(269.5 + 231)

= 20(500.5)

= 10010 sq cm

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