DA是AB边的1/3,BE是BC的1/4,CF是CA的1/5,
连接DC
S(BED)=S(BCD)/4 S(BCD)=2S(ABC)/3
S(BED)=S(ABD)/6
连接BF
S(ADF)=S(ABF)/3 S(ABF)=4S(ABC)/宴坦5
S(ADF)=4S(ABF)/15
连郑祥弊接AE
S(EFC)=S(AEC)/5 S(AEC)=3S(ABC)/4
S(EFC)=3S(ABC)/20
S(DEC)=S(ABC)-S(BED)-S(ADF)-S(EFC)
=S(ABC)*(1-1/6-4/喊族15-3/20)
=S(ABC)*5/12
S(ABC)=25*12/5=60
Sbed=1/6SABC,SECF=3/20SABC;SAFD=4/早仿15SABC (1-1/陆宏纤6-3/绝歼20-4/15)SABC=25
SABC=60
容我考虑考虑，有点难
此题 无解