如图,在△ABC中,AB=AC,∠A=36°,AB的垂直平分线交AC于点E,垂足为点D,连接BE,则∠EBC的度数为( ) A.18° B.36° C.60° D.72°
问题描述:
如图,在△ABC中,AB=AC,∠A=36°,AB的垂直平分线交AC于点E,垂足为点D,连接BE,则∠EBC的度数为( )
A. 18°
B. 36°
C. 60°
D. 72°
答
∵AB=AC,∠A=36°,
∴∠C=∠ABC=
(180°-∠A)=72°,1 2
∵DE是AB的垂直平分线,
∴AE=BE,
∴∠ABE=∠A=36°,
∴∠EBC=∠ABC-∠ABE=72°-36°=36°,
故选B.