连接BG,GC,PB,PC,分别过G,P作GG1⊥BC于G1,作PP1⊥BC于P1,则PP1‖GG1,PP1/GG1=A1P/A1G.S(△PBC)/S(△GBC)=PP1/GG1=A1P/A1G.同理,S(△PCA)/S(△GCA)=C1P/C1G.S(△PAB)/S(△GAB)=B1P/B1G.G为重心,S(△GAB)=S(△GBC)=S(...