l = 2 π r
1) l = 2 × 3.14 × 5 = 31.4 см
2) l = 2 × 3.14 × 3.5 = 21.98 м
3) l = 2 × 3.14 × 12 = 75.36 мм
3,5*2*3,14=21,98 м
12*2*3,14=75,36 мм
l = 2 π r
1) l = 2 × 3.14 × 5 = 31.4 см
2) l = 2 × 3.14 × 3.5 = 21.98 м
3) l = 2 × 3.14 × 12 = 75.36 мм