Question

Class 9th maths) the diameter of the base of the right circular cylinder is 42cm and its height is 10cm. find the area of the curved surface.

Answer 1

Here is the answer
Hope it helps! !
Please mark as brainliest! !

Answer 2

$\large\underline{ \underline{ \sf \maltese{ \: Question:- }}}$

• The Diameter of the base of a right circular cylinder is 42cm and its height is 10cm . Find the area of the curved surface and total surface area.

$\large\underline{ \underline{ \sf \maltese{ \: Given:- }}}$

• Diameter of the base of the Cylinder = 42cm
• Height of the base of the Cylinder = 10cm

Radius of of the Cylinder = ${\boxed{ \bf { \frac{Diameter}{2} }}}$

$\qquad \quad \longrightarrow \sf{\sf{\frac{Diameter}{2} }}$

$\qquad \quad \longrightarrow \sf{\sf{\frac{42}{2} \: = \: \cancel\frac{42}{2}}}$

Radius of the Cylinder = ${\boxed{ \bf { 21cm }}}$

━━━━━━━━━━━━━━━━━━━━━━━━━

$\large\underline{ \underline{ \sf \maltese{ \: To \: Find :- }}}$

• Curved Surface of the Cylinder ?

━━━━━━━━━━━━━━━━━━━━━━━━━

$\large\underline{ \underline{ \sf \maltese{ \: Solution:- }}}$

$\underbrace\purple{\boxed{ \bf \green{Curved \: Surface \: area \: of \: Cyclinder }}}$

$\begin{gathered}\begin{gathered}\begin{gathered}: \implies \underline\blue{ \boxed{\displaystyle \sf \bold\orange{\: C.S.A \: of \: a \: Cylinder \: = \:2\pi \: \times \: Radius \: \times \: Height }} }\\ \\\end{gathered}\end{gathered}\end{gathered}$

$\qquad \quad {:} \longrightarrow \sf{\bf{C.S.A \: of \: a \: Cylinder \: = \:2 \: \times \: \frac{22}{7} \: \times \: 21\: \times \: 10 }}$

$\qquad \quad {:} \longrightarrow \sf{\sf{C.S.A \: of \: a \: Cylinder \: = \:2 \: \times \: \frac{22}{ \cancel7} \: \times \: \cancel{21}\: \times \: 10 }}$

$\qquad \quad {:} \longrightarrow \sf{\sf{C.S.A \: of \: a \: Cylinder \: = \:2 \: \times \: 22 \: \times \: 3\: \times \: 10 }}$

$\qquad\quad {:} \longrightarrow \underline \red{\boxed{\sf{Curved \: Surface \: area \: of \: Cyclinder\: = \: 1320{cm}^{2} }}}$

$\begin{gathered}\begin{gathered}\qquad \therefore\: \sf{ Curved \: Surface \: area \: of \: Cyclinder \: = \underline {\underline{ 1320{cm}^{2} }}}\\\end{gathered}\end{gathered}$