l patrat = 30 cm
1) P = ? m
30 cm = 0,3 m, se fac transformarile
30 : 100 = 0.3
P = 4 · l = 4 · 0,3 = 1,2 m
P = 1,2 m
2) P = ? dam
30cm = 3 dm = 0,3 m = 0, 03 dam
P = 4 · l = 4 · 0, 03 = 0,12 dam
P = 0,12 dam
3) S = P / 2
S = ? dm
30 cm = 3 dm
S = 4· l / 2 = 2· l = 2 · 3 = 6 dm
S = 6 dm,
dm² = se foloseste cand se calculeaza aria