A)
Obw= 2*3,14*2 =12,56cm
Obw = 6,28*4 = 25,12m
Obw = 6,28*0,3 = 1,884cm
Obw = 6,28*10 = 62,8km
b)
Obw = 6,28*1 = 6,28cm
Obw = 6,28 * 1,5 = 9,42m
Obw = 6,28 *0,2 = 1,256cm
Obw = 6,28 *100 = 628m
c)
6,28*r = 10m
r≈1,59m
6,28*r = 1m
r≈0,159
6,28*r = 628mm
r=100mm
6,28*r = 3,5cm
r≈ 0,557cm