Question

The inner curved surface area of a well is 792m2and radius of its base is 21m. Find its height.

Answer 1

Given

• Inner curved surface area of a well is 792 m²
• Radius of the base is 21 m

Explanation

Let the height of the well be x and Radius is 21m so we've that :-

$\maltese{\boxed{\sf\large{ C.S.A. _{(Cylinder)} = 2πrh }}}$

$\\ \bigstar{\pmb{\underline{\sf{ According \ to \ Question: }}}} \\ \\ \colon\implies{\sf{ 792 = 2πrh }} \\ \\ \\ \colon\implies{\sf{ 792 = 2 \times \dfrac{22}{7} \times 21 \times x}} \\ \\ \\ \colon\implies{\sf{ \dfrac{ \cancel{792} \times 7}{2 \times \cancel{22} \times 21} = x }} \\ \\ \\ \colon\implies{\sf{ \dfrac{ \cancel{36} \times 7}{ \cancel{2} \times 21} = x }} \\ \\ \\ \colon\implies{\sf{ \dfrac{18 \times 7}{21} = x }} \\ \\ \\ \colon\implies{\sf{ \cancel{ \dfrac{126}{21} } = x }} \\ \\ \\ \colon\implies{\underline{\boxed{\mathfrak\pink{ x = 6 \ m}}}}$

Hence,

$\\ {\underline{\sf{ The \ Height \ of \ the \ Well \ will \ be \ \ {\sf\bold{6 \ m}} . }}}$

$\\ \\ \maltese {\pmb{\underline{\sf{ More \ to \ Know: }}}} \\ \\ \bigstar{\boxed{\sf{ Volume_{(Cylinder)} = πr^2h }}} \\ \\ \bigstar{\boxed{\sf{ T.S.A. _{(Cylinder)} = 2πr(h+r) }}}$