Question

find volume CSA and TSA of cylinder whose diameter is 21 cm height 18 cm

Answer 1

Hey Friends,

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Diameter =21 ,Radius =21/2
Height =18cm

TSA$\: = 2\pi r(r + h)$
$\: \: \: \:= 2 \times \frac{22}{7} \times \frac{21}{2} ( \frac{21}{2} + 18)$
=66(57/2)
=1881 cm^2

CSA = 2pi rh
=2×22/7×21/2
=66 cm^2
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Answer 2

Solution ●●●●
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Given,

Diameter = 21 cm

$Radius = \frac{Diameter}{2} \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{21}{2} = 10.5 \: cm$

Height = 18 cm
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$Volume \: \: of \: \: the \: \: cylinder$

$= \pi {r}^{2} h \\ \\ = (\frac{22}{7} \times 10.5 \times 10.5 \times 18) \: \: {cm}^{3} \\ \\ = 6237 \: \: {cm}^{3}$
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$CSA \: \: of \: \: the \: \: cylinder$

$= 2\pi \: rh \\ \\ =( 2 \times \frac{22}{7} \times 10.5 \times 18) \: \: {cm}^{2} \\ \\ = 1188 \: \: {cm}^{2}$
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$TSA \: \: of \: \: the \: \: cylinder$

$= 2\pi \: r(h + r) \\ \\ = 2 \times \frac{22}{7} \times 10.5 \: (18 + 10.5) \: \: {cm}^{2} \\ \\ = (66 \times 28.5) \: \: {cm}^{2} \\ \\ = 1881 \: \: {cm}^{2}$
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