Question 1107307
{{{ A = pi*r^2 }}}
{{{ r^2 = A/pi }}}
{{{ r = sqrt( A/pi ) }}}
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You are given {{{ A = 28*pi }}} 
{{{ r = sqrt( ( 28*pi ) / pi ) }}}
{{{ r = 2*sqrt(7) }}}
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Find {{{ A }}} with {{{ r/2 }}} radius
{{{ A = pi*( r/2 )^2 }}}
{{{ A = ( pi/4 )*r^2 }}}
{{{ A = ( pi/4 )*( 4*7 ) }}}
{{{ A = 7pi }}}
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check my math