A= πr²=π*([tex]2 \frac{3}{9} [/tex])²=π*([tex] \frac{7}{3} [/tex])²=[tex] \frac{49}{9} [/tex]π
d=4,(4)= [tex] \frac{40}{9} [/tex] => r= [tex] \frac{d}{2} [/tex] = [tex] \frac{40}{9} * \frac{1}{2} = \frac{20}{9} [/tex]
A=πr²= π ([tex] \frac{20}{9} [/tex])²= [tex] \frac{400}{81} [/tex] π
