已知：如图，矩形ABCD的对角线AC和BD相交于点O，AC=2AB．求*：.                 ...

问题详情：

已知：如图，矩形ABCD的对角线AC和BD相交于点O， AC=2AB．求*： .                                                                                                                       

                                                                                                         

                                                                                           

                                                                  

                                                                          

                                                                   （

【回答】

*：∵矩形ABCD ，

∴(矩形的四个角都是直角)  .

在，AC=2AB ，

∴.                   

          ∵AC=BD (矩形的对角线相等) ，  

          ∴BO=，CO =.

∵AB=CD(矩形的对角线互相平分) ，        

∴BO=CO .      

∴ .              

∵，

          ∴.                    

知识点：特殊的平行四边形

题型：解答题