设平行四边形ABCD的面积是S,设AB=5a,BC=3b.AB边上的高是3x,BC边上的高是5y.则S=5a•3x=3b•5y.即ax=by=
| S |
| 15 |
△AA4D2与△B2CC4全等,B2C=
| 1 |
| 3 |
| 4 |
| 5 |
则△AA4D2和△B2CC4的面积是2by=
| 2S |
| 15 |
同理△D2C4D与△A4BB2的面积是
| S |
| 15 |
则四边形A4B2C4D2的面积是S-
| 2S |
| 15 |
| 2S |
| 15 |
| S |
| 15 |
| S |
| 15 |
| 9S |
| 15 |
| 9S |
| 15 |
解得S=
| 5 |
| 3 |
故选C.
A. 2| 3 |
| 5 |
| 5 |
| 3 |
设平行四边形ABCD的面积是S,设AB=5a,BC=3b.AB边上的高是3x,BC边上的高是5y.| S |
| 15 |
| 1 |
| 3 |
| 4 |
| 5 |
| 2S |
| 15 |
| S |
| 15 |
| 2S |
| 15 |
| 2S |
| 15 |
| S |
| 15 |
| S |
| 15 |
| 9S |
| 15 |
| 9S |
| 15 |
| 5 |
| 3 |