Question 94092
Question:

Find the circumference of a circle with the area 36pi square centimeters?


Answer:


Area of circle is given by the formula,  A = {{{pie (r^2)}}}, where A is the area and r is the radius of the circle.



Here, A = 36 pie



==> {{{36(pie) = pie (r^2)}}}


Divide both sides of the  expression by {{{ pie }}}



==>  {{{36(pie)/(pie)  = pie (r^2)/ (pie)}}}



==>  {{{36  =  r^2}}}



Take square root on both sides...



==> {{{ sqrt (36)  = sqrt( r^2)}}}



==>  r = 6 or -6


Since radius can never be negative, you can take r = 6


So, radius = 6



Now circumference of a circle is given by the formula, {{{ 2(pie) r}}}



So circumference =  {{{ 2(pie) 6}}}



==>  {{{ 12(pie)  }}}

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If you put the approximate value of pie ( its {{{3.14}}} or {{{22/7}}} you will get


Circumference =   {{{12*(3.14)}}} 

That is, circumference =  {{{37.68}}} 



Hope you found the explanation useful.


Regards.


Praseena.