求证:有两条高相等的三角形是等腰三角形。
如图(10)已知:△ABC中,∠C=2∠B,AD平分∠BAC交BC于D。
求证:AB=AC+DC。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/72f082025aafa40f95b9e855ab64034f78f0193e?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
如图,已知:△ABC中∠BAC=∠BCA,AD是△ABC的中线,延长BC到F使CF=AB。
求证:AF=2AD。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/d1a20cf431adcbef16b8588eacaf2edda2cc9fad?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
如图,四边形ABCD的对角线AC、BD相较于点O,△ABC≌△BAD。
求证:(1)OA=OB;(2)AB∥CD
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/1b4c510fd9f9d72a5b703195d42a2834349bbb25?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
如图,∠B=∠C=90°,M是BC的中点,DM平分∠ADC. 求证: AM平分∠DAB
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/c8177f3e6709c93ddaf02f7f9f3df8dcd1005433?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
、已知:在△ABC中,BC=10, D是AC上一点且AB=BD, E, F分别是AD、BC 的中点. 求:EF的长
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/023b5bb5c9ea15ce75b0c081b6003af33b87b2df?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)