Question

Find the curved surface area of the cylinder with radius 7cm and height 4cm.​

Answer 1

Correct Question :- Find the curved surface area of a cylinder with radius 7cm and height 4cm.

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To Find :- Here, we have to find the curved surface area of the cylinder with radius and height as given.

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Diagram :- $\setlength{\unitlength}{1mm}\begin{picture}(5,5)\thicklines\multiput(-0.5,-1)(26,0){2}{\line(0,1){40}}\multiput(12.5,-1)(0,3.2){13}{\line(0,1){1.6}}\multiput(12.5,-1)(0,40){2}{\multiput(0,0)(2,0){7}{\line(1,0){1}}}\multiput(0,0)(0,40){2}{\qbezier(1,0)(12,3)(24,0)\qbezier(1,0)(-2,-1)(1,-2)\qbezier(24,0)(27,-1)(24,-2)\qbezier(1,-2)(12,-5)(24,-2)}\multiput(18,2)(0,32){2}{\sf{7 \ cm}}\put(9,17.5){\sf{4 \ cm}}\end{picture}$

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Solution :- We know that, formula to find the curved surface area of a cylinder is;

• Curved surface area = 2πrh

Applying the formula on the given information, we get,

• Curved surface area (CSA) = 2πrh
• ⟼ CSA = $\sf{2\times \dfrac{22}{7}\times7\times4}$

• ⟼ CSA = $ \sf{2 × \dfrac{22}{\cancel{7}}×\cancel{7}×4}$

• ⟼ CSA = $\sf{2×22×4}$
• ⟼ CSA = $\sf{44×4}$
• ⟼ CSA = 176 cm².

```Hence, curved surface area of the cylinder will be 176 cm².

Answer 2

Given:

Radius = 7cm

height = 4cm

Solution :

By using ----- 2πrh

=2 x 22/7 x 7 x 4

or

=

$2 \times \frac{22}{7} \times 7 \times 4$

44 x 4

= 176 cm2