Réponse :
a) P = 2πr + 2 x 5.2 = 2 x π x 1.5 + 10.4 = 3π + 10.4 ≈ .........cm
A = πr² + 3 x 5.2 = π x 1.5² + 15.6 = 2.25 π + 15.6 ≈ .............cm²
b) P = πR/2 + 2πr = π(R/2 + 2r) = π(3.2/2 + 2 x 1.6) = 4.8π = ........... cm
A = πR²/2 - πr² = π(R²/2 - r²) = π(3.2²/2 - 1.6²) = 2.56π ≈ .......... cm²
Explications étape par étape :
