S being the area of quadrilateral ABCD, [EDGB]=[DEB]+[BGD], with:[DEB]=[DAE] and [BGD]=[BCG, thus[EDGB]=S/2 In the same manner: [FAHC]= [AFC]+[CAH], with [AFC]=[ABF] and [CAH]=[CAD, thus [FAHC]=S/2 both quadrilaterals [EDGB] and [FAHC] have the same area. Applying the carpet theorem proves the proposition.
BD//EH, [EAH]+[EHD]=[EAH]+[EHB], so
ReplyDelete[BEDG]=[BED]+[BDG]=[EAD]+[BGC]=[BAH]+[FDC]=[BHD]+[BDF]=[BHF]+[FHD]=[FHC]+[FAH]=[FAHC]
S being the area of quadrilateral ABCD,
ReplyDelete[EDGB]=[DEB]+[BGD], with:[DEB]=[DAE] and [BGD]=[BCG, thus[EDGB]=S/2
In the same manner:
[FAHC]= [AFC]+[CAH], with [AFC]=[ABF] and [CAH]=[CAD, thus [FAHC]=S/2
both quadrilaterals [EDGB] and [FAHC] have the same area.
Applying the carpet theorem proves the proposition.