答案】一选择题1C2C3C4D5D6C
∵AB10cm∴AC10cm∴BC16cm20∵ABAC1060°112cm∴∠DEA∠A设∠EBDx°∴∠ABC∠C∵DEEB∵BCBD∴∠BDC∠C∵ADDE
二填空题760°60°60°108°36°36°826°或38°92cm2cm123或2三解答题解∵DE垂直平分AB∴ADBD∴∠2∠B∵ADC∠2∠B∴∠ADC2∠2∵∠1∠ACD∠ADC180°∴∠12∠290°180°即∠12∠290°∵∠1
521∠22
∴∠EBD∠EDB
13100°
14107°15416
16115°19
1775°
则∠EDBx°∴∠DEA2x°∴∠A2x°∴∠ABC3x°
∵∠DEA∠EBD∠EDB∴BDC∠A∠DBA∵∠BDC3x°
∠A∠C∠ABC180°
∴∠C3x°
∴x225
∴2x3x3x180
∴∠A2x45°
21在CD上取一点E使DEBD连结AE∵AD⊥BCDEBD∴∠2∠C∴AECE∴ABAE∴ABCE∴∠B∠1∵∠B2∠C∴∠1∠C∠2
∴ABBDCEDECD即ABBDCD
2211822911
∴∠290°∴∠236°∴∠B36°19解∵△ABC为等腰三角形∴ABAC∵DE为AB的中垂线∴ADBD∵BCCDBD26∴BCCDAD26即BCAC26
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