Odpowiedź:
[tex]\pi \: {r}^{2} = 1 \frac{9}{16} \: \: {cm}^{2} \\ \pi \: {r}^{2} = \frac{25}{16} \\ {r}^{2} = \frac{25}{16\pi}r = \sqrt{ \frac{25}{16\pi} } = \frac{5}{4 \sqrt{\pi} } = \frac{5 \sqrt{\pi} }{4\pi} \\ \\ [/tex]
[tex]ob = 2\pi \: r = 2 \pi \times \frac{5 \sqrt{\pi} }{4\pi} = \frac{5 \sqrt{\pi} }{2} \: \: cm[/tex]
