角BDC = 180-角DBC-角C
= 150-角C
= 150-角ABC
= 150 - (角DBC+角ABD)
= 120 - 角ABD
= 120 - (180 - 角A - 角ADB)
= -60 + 2 * 角ADB
= -60 +2 * (180 - 角BDC)
= 300 - 2 * 角BDC
所以角BDE = 100度
角BDC = 180-角DBC-角C
= 150-角C
= 150-角ABC
= 150 - (角DBC+角ABD)
= 120 - 角ABD
= 120 - (180 - 角A - 角ADB)
= -60 + 2 * 角ADB
= -60 +2 * (180 - 角BDC)
= 300 - 2 * 角BDC
所以角BDE = 100度