解答题-证明题 困难0.15 引用2 组卷791
在△ABC中,AB<AC,点D在AC边上,AD=AB,点E在BC边上,连接ED,满足∠DEC=∠BAC,连接AE,过点A作AF⊥BC于点F.
(1)如图1,已知∠BAC=90°,∠C=30°,且AF=2
,求线段DC的长;
(2)如图2,已知∠B+∠C=
∠BAC,求证:BE+ED= 2
AF;
(3)如图3,在(1)问的条件下,△ABC内有点P,连接AP、BP,满足∠APB=120°,过点P作PM⊥AC交于点M,过点P作PN⊥BC交于点N,连接MN,直接写出MN的最小值.
![](https://img.xkw.com/dksih/QBM/2021/2/27/2667031090126848/2671370073169920/STEM/fd943d44-a3c8-491a-b6e1-828dc18c8fe9.png?resizew=535)
![](https://img.xkw.com/dksih/QBM/2021/2/27/2667031090126848/2671370073169920/STEM/08ae0a366dbd4f0c8ca00a669fadbadd.png?resizew=263)
(1)如图1,已知∠BAC=90°,∠C=30°,且AF=2
(2)如图2,已知∠B+∠C=
(3)如图3,在(1)问的条件下,△ABC内有点P,连接AP、BP,满足∠APB=120°,过点P作PM⊥AC交于点M,过点P作PN⊥BC交于点N,连接MN,直接写出MN的最小值.
![](https://img.xkw.com/dksih/QBM/2021/2/27/2667031090126848/2671370073169920/STEM/fd943d44-a3c8-491a-b6e1-828dc18c8fe9.png?resizew=535)
![](https://img.xkw.com/dksih/QBM/2021/2/27/2667031090126848/2671370073169920/STEM/08ae0a366dbd4f0c8ca00a669fadbadd.png?resizew=263)
20-21九年级上·重庆沙坪坝·期末
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