because
∠BDC=∠CEB
therefore
∠CDA=∠BEA
∠A
=∠A
AD=AE
△ADC congruence△△ AEB
AB=AC
BD=CE
6. Because: AB//A'E'
Alternating current//alternating current
therefore
∠C=∠B'C'A '
∠B'=∠CBA
because
BB'=CC '
therefore
BC = BC
△ABC congruence△ a' b' c'
AC=A'C '
7. Because △ ABC△ a' b' c'
therefore
AB=
A b
∠B=∠B '
And because of AD. A'D' is the height of △ABC and △A'B'C' respectively.
therefore
∠ADB=∠A'D'B '
△ABD?△A ' b ' d '
therefore
AD=A'D '
8. The following is omitted
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