Réponse :
EX1
1) a) p = 2πr = 2 π x 13 = 26 π cm ≈ 81.7 cm
b) A = πr² = π x 13² = 169 π cm² ≈ 530.93 cm²
2) a) p = πD = 28 π m ≈ 88 m
b) A = πD²/4 = π x 28²/4 = 196 π m² ≈ 615.8 m
ex2
1) A = 1/2(12 x 7) = 42 cm²
2) A = 1/2(13 x 8) = 52 cm²
3) A = 1/2( 4 x 6) = 12 cm²
4) A = 15 x 8 = 120 cm²
5) A = 9 x 3 = 27 cm²
Explications étape par étape :
