Question

如图,已知在三角形ABC中,中线BD,CE交于点O,且三角形ABC的面积为60,试求四边形ADOE的面积

Answer 1

连AO.S△AOE=S△BOE,S△AOD=S△COD.∴SADOE=S△BOE+S△COD 又∴O是△ABC重心.∴OE=1/2OC.∴S△EOB=1/2S△BOC同理S△COD=1/2S△BOC.∴SBOC=S△BOE+S△COD.∴SADOE=1/3S△ABC=60/3=20.