题目内容
如图,点P、Q在△ABC的AC边上,且AP:PQ:QC=1:2:3,点R在BC边上,且BR:RC=1:2,AR与BP、BQ分别相交于D、E,则SPQED:S△ABC=______.

如图,过P、Q分别作BC的平行线,交AR于点X、Y,
∴△BER∽△QEY,△PXD∽△BRD,
∵AP:PQ:QC=1:2:3,
∴AQ=CQ,
∴AY=YR,
∴QY=
CR,
∵BR:RC=1:2,
∴QY=BR,
∴
=
=1,
=
,
=
=
=3,
=
,
∴S△BED=
•
•S△BPQ=
S△BPQ,
SPQED=
S△BPQ=
•
S△ABC=
S△ABC,
∴SPQED:S△ABC=
.
故答案为:
.

∴△BER∽△QEY,△PXD∽△BRD,
∵AP:PQ:QC=1:2:3,
∴AQ=CQ,
∴AY=YR,
∴QY=
| 1 |
| 2 |
∵BR:RC=1:2,
∴QY=BR,
∴
| BE |
| EQ |
| BR |
| QY |
| BE |
| BQ |
| 1 |
| 2 |
| BD |
| DP |
| BR |
| PX |
| ||
|
| BD |
| BP |
| 3 |
| 4 |
∴S△BED=
| 1 |
| 2 |
| 3 |
| 4 |
| 3 |
| 8 |
SPQED=
| 5 |
| 8 |
| 5 |
| 8 |
| 1 |
| 3 |
| 5 |
| 24 |
∴SPQED:S△ABC=
| 5 |
| 24 |
故答案为:
| 5 |
| 24 |
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