Aire DAM = (16×20)/2 = 320/2 = 160cm²
On peut utiliser thales:
MR/MD = RO/RE
RO = (MRĂ—RE)/MD
RO = (4Ă—16)/(20-4) = 64/16 = 4cm
Aire MRO = (4×4)/2 = 16/2 = 8cm²
AE/AD = LE/MD
LE = (AEĂ—MD)/AD
LE = (4Ă—20)/16 = 5cm
Aire LEA = (LE×EA)/2 = (5×4)/2 = 20/2 = 10cm²
Le quart de l'aire de DAM
160/4 = 40cm²
or Aire LEA + Aire MRO = 10+8 = 18cm²
Donc oui il exagère.
