Question

the circumference of the base of a cylinder is 40cm and height 12cm,then the curved surface area is​

Answer 1

$\small \bf \blue{hey \: mate \: here \: is \: ur \: ans} \\ \\ \small \bf \blue{ \huge \: solution} \\ \\ \small \bf \blue{given \: that} \\ \\ \small \bf \blue{circumference \: of \: the \: base \: of \: } \\ \small \bf \blue{cylinder = 40 \: cm} \\ \\ \small \bf \blue{2\pi \: r = 40} \\ \\ \small \bf \blue{r = \frac{40}{2 \: \pi} } \\ \\ \small \bf \blue{r = \frac{20}{\pi} } \\ \\ \small \bf \blue{r = 20 \times \frac{7}{22} } \\ \\ \small \bf \blue{r = \frac{140}{22} } \\ \\ \small \bf \blue{r = \frac{70}{11} \: cm } \\ \\ \small \bf \blue{h =12 \: cm } \\ \\ \small \bf \blue{ \therefore \boxed{ \bf \pink{csa = 2 \: \pi \: r \: h}}} \\ \\ \small \bf \blue{}\\ \small \bf \blue{ \therefore \boxed{ \bf \pink{csa = 2 \times \frac{22}{7} \times \frac{70}{11} \times 12 }}} \\ \\ \\ \small \bf \blue{ \therefore \boxed{ \bf \pink{csa = \frac{44 \times 10 \times 12}{11} }}} \\ \\ \small \bf \blue{}\\ \small \bf \blue{ \therefore \boxed{ \bf \pink{csa = \frac{5280}{11} }}} \\ \\ \small \bf \blue{}\\ \small \bf \blue{ \therefore \boxed{ \bf \pink{csa = 480 \: c {m}^{2} }}}$