题干
如果线段a、b、c、d满足
=
=
，那么
=____．
| a |
| b |
| c |
| d |
| 1 |
| 3 |
| a |
| + |
| c |
| b |
| + |
| d |
答案(点此获取答案解析）
| 1 |
| 3 |
