Odpowiedź:
[tex]1. \: l = 2\pi \: \times r = 2\pi \times 4cm = 8\pi \: cm = odp.b[/tex]
2. BD
[tex]3. \: a) \: l = 2\pi \times r = 2\pi \times 2 \frac{2}{3} = 2\pi \times \frac{8}{3} = \frac{16}{3} \pi = 5 \frac{1}{3} \pi[/tex]
[tex]b) 2\pi \times r = l \\ r = \frac{l}{2\pi} \\ r = \frac{1 \frac{1}{3} \pi}{2\pi} = \frac{4}{3} \times \frac{1}{2} = \frac{4}{6} = \frac{2}{3}cm [/tex]
[tex]c) \: 2\pi \times r = l \\ r = \frac{l}{2\pi} \\ r = \frac{3 \frac{3}{5}\pi }{2\pi} = \frac{18}{5} \times \frac{1}{2} = \frac{18}{10} = 1.8cm \\ 2r = 1.8cm \times 2 = 3.6cm[/tex]
