Question

Find the curved surface area of a cylinder whose radius
is 21 cm and neight is 4 cm​

Answer 1

Question:-

Find the curved surface area of a cylinder whose radius is 21cm and height is 4cm.

Required Answer:-

Given:-

$\\ \sf{ \rightarrow{Radius \: of \: the \: cylinder = 21cm}}$

$\sf{ \rightarrow{Height \: of \: the \: cylinder = 4cm}}$

To Find:-

$\\ \sf{ \rightarrow{Curved \: serface \: area \: of \: the \: cylinder}}$

♡Solution:-

As we know that:-

$\\ \underline{\boxed{\sf{ \blue{ \bold{Curved \: surface \: area} = 2\pi \: rh \: sq.units}}}}$

We were given :-

• Radius r = 21cm
• Height h = 4cm

Substituting the values:-

$\\ \sf{ \bold{Curved \: surface \: area }= 2 \times \pi \times 21cm \times 4cm}$

$\\ \sf{ \implies{ \bold{Curved \: surface \: are} =( 2 \times \frac{22}{7} \times 21 \times 4) {cm}^{2} }}$

$\\ \sf{ \therefore{ \bold{Curved \: surface \: are} = \red{528cm {}^{2} }}}$

$\\ \\ \boxed{ \green{ \rm{Hence, \: curved \: surface \: area \: of \: the \: cylinder \: is \: \bold{528cm {}^{2} }}}}$

Answer 2

Answer:

$\huge{ \boxed{ \red{ \rm{528sq.cm}}}}$

Step-by-step explanation:

Given:-

• Radius of the cylinder r = 21cm
• Height of the cylinder h = 10cm

To find:-

• Curved surface area.

Solution:-

The formula of curved surface area of cylinder:-

2πrh sq.units

Substituting the values:-

(2 × 22/7 × 21 × 10) sq. cm

=> (11/7 × 210) sq. cm

=> 528 sq.cm

Hence, the curved surface area of the cylinder is = 528 sq. cm.