6.如下图,点D,E再三角形ABC的边BC上,AB=AC,AD=AE,求证BD=CE.

问题描述:

6.如下图,点D,E再三角形ABC的边BC上,AB=AC,AD=AE,求证BD=CE.

证明:
∵AB=AC
∴∠B=∠C
∵AD=AE
∴∠ADE=∠AED
∵∠ADE=∠BAD+∠B
∠AED=∠CAE+∠C
∴∠BAD=∠CAE
∴△ABD≌△ACE
BD=CE