[tex]Zad. 1\\l = 2\pi r\\P=\pi r^2\\\\r = 1,5cm\\l=2*1,5cm \pi = 3\pi cm\\\\P= \pi* (1,5cm)^2=2,25\pi cm^2[/tex]
[tex]Zad. 2\\l = 30\pi\\l=2\pi r\\30\pi = 2\pi r\\30 = 2r /:2\\15=r\\P=\pi*15^2=225\pi = 225*3,14=706,5\\[/tex]
[tex]Zad. 3\\d = 20m\\r= \frac{d}2\\r_1 = 10m\\r_2=10m+1m=11mn\\\\P_1 = \pi * (10m)^2=100\pi m^2\\P_2 = \pi * (11m)^2 = 121\pi m^2\\\\P_s=P_2-P_1\\P_s=121\pi m^2-100\pi m^2=21 \pi m^2\\\text{Pole sciezki biegnacej wzdluz tego trawnika ma pole } 21 \pi m^2[/tex]
