英文數學題6,急急

2006-11-17 5:08 am

In the figure (http://hk.geocities.com/ken1ken1232003/ABCDM.bmp),
AB=CDand BC=DA.
(a)Prove that angle ADB=angle CBD and angle ABD=angle CDB.
(b)Prove that AC and BD bisect each other.

註:要列式及解釋問題!

回答 (1)

用戶3640

2006-11-17 5:26 am

✔ 最佳答案

a.AD=CB(given)
AB=CD(given)
DB=BD(common side)

∴ △ABDis congruent to△CDB(SSS)

∴ ∠ ADB=∠ CBDand ∠ ABD=∠ CDB(corr.∠s,congruent △)

b.∠ADM=∠CBM(proved)

∠ AMD=∠ CMB(vert. opp. angles)

AD=CB(given)

∴ △AMD is congruent to △CMB

∴ AM=CM and MD=MB(corr. sides,congruent△)

∴ACand BD bisect each other

2006-11-16 21:27:41 補充：
∴ △AMD is congruent to △CMB(AAS)

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收錄日期: 2021-04-22 00:13:30
原文連結 [永久失效]:
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