pole koła = P_1=\pi r^2
pole kwadratu = P_2=a^2
2\pi r=4a |:2pi
wyznaczam r
r=\frac{4a}{2\pi}
r=\frac{2a}{\pi} promień okręgu
P_1=\pi r^2=\pi *(\frac{2a}{\pi})^2=\pi *\frac{4a^2}{\pi^2}=\frac{4a^2}{\pi} pole koła
\frac{P_1}{P_2}=\frac{\frac{4a^2}{\pi}}{a^2}=\frac{4a^2}{\pi}*\frac{1}{a^2}=\frac{4}{\pi}
\frac{P_1}{P_2}=\frac{4}{\pi} <–odpowiedź