Question

Find the area of a semi circle of radius 3.2cm.(Use pie =22/7)​

Answer 1

Step-by-step explanation:

Area of a circle is given by πr^2 if r is the radius. therefore area of a semicircle of the radius r is

$\frac{1}{2} (\pi \times r {}^{2} )$

here

$r = 3.2cm$

therefore

$area = \frac{1}{2} (\pi \times r {}^{2} ) = \frac{1}{2} ( \frac{22}{7} \times 3.2 {}^{2} ) = \frac{1}{2} \times ( \frac{22}{7} \times 10.24) = \frac{11}{7} \times 10.24 = 16.091cm {}^{2}$

Answer 2

${ \rm{ \huge \underline{ Given}}}$

${ \rm{ \large { \to The \: radius \: of \: semi \: circle = 3.2cm}}}$

${ \rm{ \huge \underline{ To \: Find}}}$

${ \rm{ \large { \to The \: area \: of \: semi \: circle }}}$

${ \rm{ \huge \underline{ Solution}}}$

${ \rm{ \dfrac{1}{2}( \pi {r}^{2}) = area}} \\ = \dfrac{1}{2} \times \dfrac{22}{7} \times {(3.2)}^{2}$

${ \rm{ = \dfrac{1}{2} \times \dfrac{22}{7} \times 32 \times 32 }}$

${ \rm{1609.1cm}}$

${ \rm{Ans \colon The \: area \: of \: the \: semi \: circle \: is \: 1609.1cm}}$