Bonjour,
1: P = 2(L + l) = 2(9 + 12) = 42 hm
2: A = L x l = 9 x 12 = 108 hm²
3: P = 4c = 4 x 13 = 52 cm
4: A = c² = 13² = 169 cm²
5: P = 4c = 252 dm <=> c = 252/4 = 63 dm
6: r = D/2 = 14/2 = 7 mm
7: P = pi x D = pi x 14 = 43,98 mm
8: A = pi x r² = pi x 7² = 153,94 mm
9: P = 2(L + l) = 2L + 2l <=> L = (P - 2l)/2 = 38/2 - 6 = 13 m
10: A = L x l = 13 x 6 = 78 m²
11: A = c² <=> c = [tex]\sqrt{A}[/tex] = [tex]\sqrt{121}[/tex] = 11 km
12: P = 4c = 4 x 11 = 44 km
