a) AB = 20 mm = 2 cm
BC = 1,2 cm
AC = 0.1 dm = 1 cm
P = 2 + 1,2 + 1 = 4,2 cm
b) AB = 0,25 hm = 25 m
BC = 31 m
AC = 12 m
P = 25 + 31 + 12 = 68 m
2800 cm = 280 dm
18 dam = 1800 dm
3 m = 30 dm
2,5 km = 25000 dm
920000 (care e unitatea de masura?) = ... dm
19 hm = 19000 dm