如图,BE,CF是△ABC的角平分线,∠A=65°,那么BDC等于( ) A.122.5° B.187.5° C.178.5° D.115°
问题描述:
如图,BE,CF是△ABC的角平分线,∠A=65°,那么BDC等于( )
A. 122.5°
B. 187.5°
C. 178.5°
D. 115°
答
∠BDC=180°-(∠DBC+∠DCB),
=180°-
(∠ABC+∠ACB),1 2
=180°-
(180°-∠A),1 2
=90°+
∠A,1 2
=122.5°.
故选A.