【单选题】I'm not as lucky as Veronica.
【单选题】在平行四边形ABCD中,AC与BD交于点O,E是线段OD的中点,AE的延长线与CD交于点F。若 = a , = b ,则 = [ ]
【单选题】Which of the following is correct about the news?
A.
Veronica Lario will apologize to Silvio Berlusconi.
B.
The 72-year-old minister has taken part in a birthday party with his wife.
C.
Veronica Lario has clashed with Silvio Berlusconi more than three times.
D.
Silvio Berlusconi is a billionaire.
【单选题】I'm not as lucky as Veronica.
【简答题】已知:在四边形ABCD中,AC=BD,AC与BD交于点O,∠DOC=60度. (1)当四边形ABCD是平行四边形时(如图1),证明AB+CD=AC; (2)当四边形ABCD是梯形时(如图2),AB ∥ CD,线段AB、CD和线段AC之间的数量关系是______; (3)如图3,四边形ABCD中,AB与CD不平行,结论AB+CD=AC是否仍然成立?如果成立,请给予证明;如果不成立,请说明理由.
【简答题】为什么车上的镀铬装饰条等部件表面会有污点?
【简答题】已知:在四边形ABCD中,AC = BD,AC与BD交于点O,∠DOC = 60°. (1)当四边形ABCD是平行四边形时(如图1),证明AB + CD = AC; (2)当四边形ABCD是梯形时(如图2),AB∥CD,线段AB、CD和线段AC之间的数量关系是_____________________________; (3)如图3,四边形ABCD中,AB与CD不平行,结论AB + CD = AC...
【简答题】已知:在四边形ABCD中,AC = BD,AC与BD交于点O,∠DOC = 60°. 小题1:当四边形ABCD是平行四边形时(如图1),证明AB + CD = AC; 小题2:当四边形ABCD是梯形时(如图2),AB∥CD,线段AB、CD和线段AC之间的数量关系是_____________________________; 小题3:如图3,四边形ABCD中,AB与CD不平行,结论AB + CD =...
【简答题】(5分)在平行四边形ABCD中,对角线AC与BD交于点O, ,则λ=____.