Question

The height of a right circular cylinder with curved surface area 792sq.cm is 21cm. Find the radius of
the base.
pleasee answer fast please

Answer 1

Given

• Height of the cylinder = 21cm
• Curved surface area of the cylinder = 792cm².

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To find

• Radius of the base of the cylinder.

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Solution

• Let the radius be r.

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We have Curved surface area of the cylinder.

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• As we know

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☆ CSA (cylinder) = 2πrh

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→ CSA = 792

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→ 2πrh = 792

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→ 2 × 22/7 × r × 21 = 792

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→ 2 × 22 × r × 3 = 792

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→ 132 × r = 792

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→ r = 792/132

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→ r = 6

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Hence,

• Radius of the base of the cylinder is 6cm.

Answer 2

12cm is the αnswer.

Step-by-step explanation:

Given,

• Height of the cylinder = 21cm
• Lateral surface area = 792cm²

Let the radius be ' r'

We know that ,

Lateral surface area of a cylinder = 2πrh

$\sf 792=2\times\dfrac{22}{7}\times r \times 21 \\ \sf \dfrac{792\times2}{2\times 22\times 21 } =r$

r = 6

Radius = 6cm

Diameter = 2 × radius = 2 × 6cm = 12cm

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hope it elps! :p