bonjour
AB² = 50² - 40 ²
AB² = 900
AB = √900 = 30 m
CA/CE = CB/CD = AB/ED
40/100 = 30 /ED ⇔ ED = 75 m
( 40 * 30) / 2 = 600
aire ABC = 600 m²
( 100 * 75 ) /2 = 3 750
aire CEd = 3 750 m²
pour 600 m² il met 40 min
pour 3 750 m² il mettra 250 min = 4 h 10 min