电子课本网 第26页

第26页

信息发布者:
A
ABE
ACE
$95^{\circ}$
$65^{\circ}$
​$ AC$​
​$ BC$​
​$ ACD$​
​$ BCE$​
​$ AC$​
​$ BC$​
已证
​$ ACD$​
​$ BCE$​
SSS
全等三角形的对应角相等
(1)解:在$\triangle ABC$和$\triangle ADE$中,
$\begin{cases}AB = AD \\BC = DE \\AC = AE\end{cases}$
$\therefore \triangle ABC\cong\triangle ADE(SSS)$
$\therefore \angle BAC=\angle DAE$
$\therefore \angle BAC - \angle DAC=\angle DAE - \angle DAC,$即$\angle BAD=\angle CAE = 38^{\circ}$
(2)证明:由(1)知,$\triangle ABC\cong\triangle ADE,$$\angle BAD=\angle CAE$
$\therefore \angle C=\angle E$
又$\because \angle E+\angle AFE+\angle CAE = 180^{\circ},$$\angle C+\angle CFD+\angle CDE = 180^{\circ},$$\angle AFE=\angle CFD$
$\therefore \angle CDE=\angle CAE$
$\because \angle BAD=\angle CAE$
$\therefore \angle CDE=\angle BAD$