如图,
中,
,
,点D是AC的中点,过点D作
交BC于点E,连接AE.若
,求BC的长.
![](https://img.xkw.com/dksih/QBM/2021/11/6/2845718151274496/2846891781160960/STEM/62f79a17-568a-4e94-ab33-c2eed673d681.png)
解:∵
.
∴
(_____________________________)
∵
,∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68e744f480e11f588570c5d6738799f5.png)
∴
________________°
∵点D是AC的中点,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68fbbd17c89f03dbb61cd6ffdb9a0344.png)
∴
(_____________________________)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6e9e0417793b1afa51ba616bd060dd6.png)
∴
________________°
∵在
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
∴
________________=________________
∴
________________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68fbbd17c89f03dbb61cd6ffdb9a0344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86338536656046e93b53672ade9a78b3.png)
![](https://img.xkw.com/dksih/QBM/2021/11/6/2845718151274496/2846891781160960/STEM/62f79a17-568a-4e94-ab33-c2eed673d681.png)
解:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca84044d0e1de6c7540879ed3a55bb12.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68e744f480e11f588570c5d6738799f5.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d78a47604a27622ac44527404ec9061.png)
∵点D是AC的中点,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68fbbd17c89f03dbb61cd6ffdb9a0344.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c91212dd0b95b3146f2bdcc48531088f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6e9e0417793b1afa51ba616bd060dd6.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc4dbb8471a0cba5510587293f323b.png)
∵在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1a3b94566843e92ce775ff6bdf386fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d3c9ce32b721995f355eea411340e3.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6334b72607868229fec1ba27bf0b142c.png)
更新时间:2021-11-08 15:19:04
|
相似题推荐
解答题-证明题
|
较易
(0.85)
【推荐1】如图,在正方形
中,
是对角线
上的一点,连接
、
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/553a93e0b6156befa00b50bdfaef95d9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/25/6102bebd-6c81-4e3f-8364-9350d872ef0c.png?resizew=116)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
名校
【推荐2】如图,在
中,
,BE平分
,AM
BC于点M,AD平分
,交BC于点D,AM交BE于点G.
![](https://img.xkw.com/dksih/QBM/2020/11/10/2590074794827776/2595403375042560/STEM/daf43d1b97914382a0d09a06d0f986bf.png?resizew=222)
(1)求证:
;
(2)判断直线BE是否垂直平分线段AD,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65b57dcaff8632c9a3d5190fb79db868.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee2ba015fc9f3700a8c9ccc423cf1c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43ee49ad5a0dd93c96afa428ce55bc00.png)
![](https://img.xkw.com/dksih/QBM/2020/11/10/2590074794827776/2595403375042560/STEM/daf43d1b97914382a0d09a06d0f986bf.png?resizew=222)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8b0823c6baf87482ce9fd5733f6ac50.png)
(2)判断直线BE是否垂直平分线段AD,并说明理由.
您最近一年使用:0次
解答题-计算题
|
较易
(0.85)
【推荐2】如图,在
中,
于点
,
,
,
.
(1)求
的大小;
(2)若点
,
分别为
,
的中点,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7099026716ee1821dd7d9f157dc055f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1719410d21e3de1242366ce2965e838c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ed75e65e7374c38ffb1f75259a8beb.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/100c5c15-c4fd-493e-956d-14a1df3fd173.png?resizew=148)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
您最近一年使用:0次
解答题-作图题
|
较易
(0.85)
名校
【推荐1】如图,在Rt△ABC中,∠BCA=90°,∠A=30°.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/11/281beb98-addc-414c-bf30-a417c5375563.png?resizew=202)
(1)请在图中用尺规作图的方法作出AB的垂直平分线交AC于点D,并标出D点;(不写作法,保留作图痕迹).
(2)在(1)的条件下,连接BD,求证:BD平分∠CBA.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/11/281beb98-addc-414c-bf30-a417c5375563.png?resizew=202)
(1)请在图中用尺规作图的方法作出AB的垂直平分线交AC于点D,并标出D点;(不写作法,保留作图痕迹).
(2)在(1)的条件下,连接BD,求证:BD平分∠CBA.
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
【推荐2】如图,四边形
中,
,且
.
的长;
(2)求
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4657706c4d77d374e0177c5550aa9bf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4189a0821a0ffab9dc171ecd279ba442.png)
您最近一年使用:0次