Question

Diameter of the base of a cone is 12 cm and its slant height is 7cm. Find its curved surface area.

Answer 1

Answer:

132 cm²

PLEASE MARK ME THE BRAINLIEST......

Answer 2

Given:

• Diameter of base of cone = 12 cm
• Radius of base of cone = 12/2 = 6 cm
• Slant height of cone = 7 cm

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Need to find:

• Curved surface area (CSA) of cone?

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Solution:

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$\setlength{\unitlength}{1.8mm}\begin{picture}(5,5)\thicklines\put(0,0){\qbezier(1,0)(12,3)(24,0)\qbezier(1,0)(-2,-1)(1,-2)\qbezier(24,0)(27,-1)(24,-2)\qbezier(1,-2)(12,-5)(24,-2)}\put(-0.5,-1){\line(1,2){13}}\put(25.5,-1){\line(-1,2){13}}\multiput(12.5,-1)(2,0){7}{\line(1,0){1}}\multiput(12.5,-1)(0,4){7}{\line(0,1){2}}\put(16,1.6){\sf{6 cm}}\put(22,10){\sf{7 cm}}\end{picture}$

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$\bf Here \begin{cases} & \sf{Radius,\;r = \bf{6\;cm}} \\ & \sf{Slant\;height,\;l = \bf{7\;cm}} \end{cases}$

As we know that,

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$\star\;{\boxed{\sf{\purple{Curved\;surface\;area_{\;(cone)} = \pi rl}}}}$

$:\implies\sf CSA_{\;(cone)} = \dfrac{22}{ \cancel{7}} \times 6 \times \cancel{7}$

$:\implies\sf CSA_{\;(cone)} = 22 \times 6$

$:\implies{\underline{\boxed{\sf{\pink{CSA_{\;(cone)} = 132\;cm^2}}}}}\;\bigstar$

$\therefore\;{\underline{\sf{Thus,\;Curved\;surface\;area\;of\;cone\;is\; \bf{132\;cm^2}.}}}$

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$\boxed{\underline{\underline{\bigstar \: \bf\:Formula\:Related\:to\:cone\:\bigstar}}}$

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$\sf (i)\; Curved\;surface\;area\;cone\; = \; \red{\pi rl}$

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$\sf (ii)\;Total\;surface\;area\;of\;cone\; = \; \purple{\pi r(l + r)}$

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$\sf (iii)\; Volume\;of\;cone\; = \; \pink{ \dfrac{1}{3} \pi r^2h}$