( 4分)如图,EF//AD,=.说明:∠DGA+∠BAC=180°.请将说明过程填写完成.
解:∵EF//AD,(已知)
∴=_____.(_____________________________).
又∵=,(______)
∴=,(________________________).
∴AB//______,(____________________________)
∴∠DGA+∠BAC=180°.(_____________________________)
( 4分)如图,EF//AD,=.说明:∠DGA+∠BAC=180°.请将说明过程填写完成.
解:∵EF//AD,(已知)
∴=_____.(_____________________________).
又∵=,(______)
∴=,(________________________).
∴AB//______,(____________________________)
∴∠DGA+∠BAC=180°.(_____________________________)