![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191119/20191119121539-64200.png) (1)不是正方形的菱形: ∵四边形ABCD是菱形, ∴AB=BC=CD=AD, 菱形ABCD周长为:4AB=4×=4=8cm;
(2)不是正方形的矩形: 如图所示:
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191119/20191119121539-12454.png)
∵AE=DE=BF=CF=4cm,AB=CD=2cm, ∴矩形ABCD的周长为:AB+BC+CD+AD=4+4+4+4+2+2=20cm.
(3)不是矩形和菱形的平行四边形:
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191119/20191119121540-80488.png)
如图所示: ∵AE=DE=BF=CF=2,AB=CD==2cm; ∴平行四边形ABCD的周长为:AB+BC+CD+AD=2+2+2+2+2+2=8+4cm;
(4)等腰梯形: 如图所示:
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191119/20191119121540-42622.png)
∵AD=BE=EF=CF=2,AB=CD==2cm; ∴等腰梯形ABCD的周长为:AB+BC+CD+AD=2+6+2+2=8+4cm. |