bonsoir
BD² = 5.5² + 1.5² = 32.5
BD = √32.5
CD² = 32.5 - 6.5 ² = 20.25
CD = √20.25 = 4.5
Périmètre = 3.5 + 4.5 + 1.5 + 5.5 = 15 m
15 * 2.5 = 37.50€
aire BCD = ( 4.5 x 3.5 ) / 2 = 7.875 m²
aire BDA = ( 5.5 x 1.5 ) / 2 = 4.125
aire = 12 m²
12 x 3 = 36 €
