如图,已知△ABC为等腰直角三角形,∠ACB=90°,AC=BC,D为AB上任意一点,∠CDE=∠CBE=90°1.求证:AD=DE 2.若D为BC延长线上一点,其他条件不变,(1)中的结论还成立吗?画图并证明你的结论.
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如图,已知△ABC为等腰直角三角形,∠ACB=90°,AC=BC,D为AB上任意一点,∠CDE=∠CBE=90°1.求证:AD=DE 2.若D为BC延长线上一点,其他条件不变,(1)中的结论还成立吗?画图并证明你的结论.
如图,已知△ABC为等腰直角三角形,∠ACB=90°,AC=BC,D为AB上任意一点,∠CDE=∠CBE=90°
1.求证:AD=DE 2.若D为BC延长线上一点,其他条件不变,(1)中的结论还成立吗?画图并证明你的结论.
如图,已知△ABC为等腰直角三角形,∠ACB=90°,AC=BC,D为AB上任意一点,∠CDE=∠CBE=90°1.求证:AD=DE 2.若D为BC延长线上一点,其他条件不变,(1)中的结论还成立吗?画图并证明你的结论.
过D作DF⊥AB交BC于F,因为∠FBD=45°,则∠BFD=45°,△BDF为等腰直角三角形,所以BD=DF从而∠DFC=135°,也有∠DBE=135°即∠DFC=∠DBE
再看这两个三角形易知∠1=∠2.从而有△CDF全等于△DBE,故CD=DE.
1. when did you go to park with your parents?
2. where did she go on her holiday?
3. what did he do on his holiday?
1.When did you go to a park with your parents?
2.Where did she go on her holiday?
3.He didn't buy presents on his holiday.
Did he buy presents on his holiday?
What did he do on his holiday?