Question

find the cylinder whose diameter is 42cm and the area of its curved surface is11880sq.cm
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Answer 1

Answer:

Given data

diameter = 42cm

radius = 42/2=21cm

curved surface area = 11880sq. cm

as we all know curved surface area of cylinder= 2πrh.

so, 2πrh = 11880

2(22/7)(21)(h) = 11880

132(h) = 11880

so, h = 11880/132

h = 90cm

Therefore height of the cylinder = 90cm.

Answer 2

Correct Question :

➥ Find the height whose diameter is 42cm and the area of its curved surface is 11880 cm².

Answer :

➥ The height of the cylinder = 90 cm

Given :

➤ Diameter of the cylinder = 42 cm

➤ Curved surface area of cylinder = 11880 cm²

To Find :

➤ Height of the cylinder = ?

Solution :

Let ,

The height of the cylinder be "h"

◈ Radius = ⁴²/₂ = 21 cm

As we know that

$\tt{:\implies C.S.A_{(cylinder)} = 2 \pi rh}$

$\tt{:\implies 11880 = 2 \times \dfrac{22}{ \cancel{ \: 7 \: }} \times \cancel{21} \times h}$

$\tt{:\implies 11880 = 2 \times 22 \times 3 \times h}$

$\tt{:\implies 11880 = 44 \times 3 \times h}$

$\tt{:\implies 11880 = 132 \times h}$

$\tt{:\implies 11880 = 132 \: h}$

$\tt{:\implies \cancel{\dfrac{11880}{132}} = h }$

$\bf{:\implies \underline{ \: \: \underline{ \purple{ \: \: h = 90 \: cm \: \: }} \: \: }}$

Hence, the height of the cylinder is 90 cm.