- Define H and M the intersections of FG x CE and FG x DE (see problem 171) - From problem 170, [CED]=[ABCD]/2 - [ABFG]=[DCFG]=[ABCD]/2 - [ABFG]=S1+[HEM] +S2=[DCFG]=[FCH]+S+[DGM] - From problem 171 : [HEM] =[FCH]+[DGM] - Therefore S1+S2=S
With the help of problem 170, [CED]=[ABCD]/2, also, it is easy to see that [ABFG]=[ABCD]/2 So, [CED]=[ABFG], and by eliminating the blue area in between, S=S1+S2
by Proposed Problem 170,
ReplyDelete[CED]=[ABCD]/2=[BAGF]
Please detail explanation
Delete- Define H and M the intersections of FG x CE and FG x DE (see problem 171)
ReplyDelete- From problem 170, [CED]=[ABCD]/2
- [ABFG]=[DCFG]=[ABCD]/2
- [ABFG]=S1+[HEM] +S2=[DCFG]=[FCH]+S+[DGM]
- From problem 171 : [HEM] =[FCH]+[DGM]
- Therefore S1+S2=S
With the help of problem 170, [CED]=[ABCD]/2,
ReplyDeletealso, it is easy to see that [ABFG]=[ABCD]/2
So, [CED]=[ABFG], and by eliminating the blue area in between, S=S1+S2