Question

如图,锐角△ABC中,D,E分别是AB,AC边上的点,△ADC≌△ADC′, △AEB≌△AEB′,且C′D∥

Answer 1

(180-2x)°

设∠ABC=Y,∠ACB=Z,

易得∠CEB'=Z,∠BDC'=Y

∠CDB=∠C'DB=Y,∠CEB=∠CEB'=Z

∠EBC=180-2Z,∠DCB=180-2Y

∠BFC=180-∠EBC-∠DCB=180-2X