∴∠BAE=∠C=60，AB=AC，

In △ABE and △CAD

AE=CD

∠EAB=∠C

CA=AB

∴△ABE≌△CAD(SAS)，

∴∠ABE=∠CAD，

∴∠bfd=∠abe+∠bad=∠cad+∠baf=∠bac=60；

For BG⊥AD, the vertical foot is g,

∫∠BFD = 60，

∴∠FBG=30，

That is BF = 2fg = 4.

Easy BG=2√3

So the circumference is BF+FG+GB=6+2√3.

Pure hand tour, please ask questions if you have any questions. If satisfied, O(∩_∩)O hopes to adopt it.