prove parallelogram.

2008-06-14 11:27 pm

回答 (2)

2008-06-15 1:23 am
✔ 最佳答案
AD=BC(given)
∠ADB=∠DBC(givven)
BD=BD(given)
∴ΔADB is corngent to ΔCDB (S.A.S.)
∵ΔADB is corngent to ΔCDB
∴∠BCD=∠DAB
∴∠DBA=∠CDB(∠sum ofΔ)
∴∠DBA+∠CBD=∠CDB+∠ADB
∵∠BAD=∠DCB,∠ADC=∠CBA
∴AB//CD, AD//BC
∴ABCD is a parallelogram(definition of //gram)
參考: Myself
2008-06-14 11:42 pm
Yes!you're correct!
參考: me


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