如图,AB=AC,∠ABC=70°,∠ABC的角平分线及△ABC的外角平分线相交于D,则∠CAD的度数是_.
问题描述:
如图,AB=AC,∠ABC=70°,∠ABC的角平分线及△ABC的外角平分线相交于D,则∠CAD的度数是______.
答
∵AB=AC,∠ABC=70°,
∠B=∠ACB=70°,
∵∠CAF是△ABC的外角,
∴∠CAF=∠ABC+∠ACB=140°,
∵AD是∠CAF的平分线,
∴∠CAD=
∠CAF=70°.1 2
故答案为:70°.