Bonjour;
2 cm 15m 3m 1,4dm
5 cm 3dam 3,5m 1,25dm
5cm² 225m² 10,5m² 1,75dm²
(2*5)/2= 5
3dam = 30m
(15*30)/2 = 225
10,5/3 = 3,5
1,75/1,4 = 1,25