Prove that $AD cdot AD' = AE cdot AE'$. Announcing the arrival of Valued Associate #679: Cesar...

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Prove that $AD cdot AD' = AE cdot AE'$.



Announcing the arrival of Valued Associate #679: Cesar Manara
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$begingroup$


enter image description here




Circle diameter $BC$ cuts side $AB$ and $AC$ of $triangle ABC$ respectively $C'$ and $B'$. $E$ and $E'$ are points respectively on $BC$ and the circumcircle of $AB'C'$ such that $EE'$ passes through $A$ and $EE'$ cuts the circle diameter $BC$ at $D$ and $D'$. Prove that $AD cdot AD' = AE cdot AE'$.




I tried proving that $AE cdot AE' = AM^2$ with $AM$ is a tangent of the circle diameter $BC$.










share|cite|improve this question











$endgroup$

















    1












    $begingroup$


    enter image description here




    Circle diameter $BC$ cuts side $AB$ and $AC$ of $triangle ABC$ respectively $C'$ and $B'$. $E$ and $E'$ are points respectively on $BC$ and the circumcircle of $AB'C'$ such that $EE'$ passes through $A$ and $EE'$ cuts the circle diameter $BC$ at $D$ and $D'$. Prove that $AD cdot AD' = AE cdot AE'$.




    I tried proving that $AE cdot AE' = AM^2$ with $AM$ is a tangent of the circle diameter $BC$.










    share|cite|improve this question











    $endgroup$















      1












      1








      1


      2



      $begingroup$


      enter image description here




      Circle diameter $BC$ cuts side $AB$ and $AC$ of $triangle ABC$ respectively $C'$ and $B'$. $E$ and $E'$ are points respectively on $BC$ and the circumcircle of $AB'C'$ such that $EE'$ passes through $A$ and $EE'$ cuts the circle diameter $BC$ at $D$ and $D'$. Prove that $AD cdot AD' = AE cdot AE'$.




      I tried proving that $AE cdot AE' = AM^2$ with $AM$ is a tangent of the circle diameter $BC$.










      share|cite|improve this question











      $endgroup$




      enter image description here




      Circle diameter $BC$ cuts side $AB$ and $AC$ of $triangle ABC$ respectively $C'$ and $B'$. $E$ and $E'$ are points respectively on $BC$ and the circumcircle of $AB'C'$ such that $EE'$ passes through $A$ and $EE'$ cuts the circle diameter $BC$ at $D$ and $D'$. Prove that $AD cdot AD' = AE cdot AE'$.




      I tried proving that $AE cdot AE' = AM^2$ with $AM$ is a tangent of the circle diameter $BC$.







      geometry euclidean-geometry circles






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      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Mar 24 at 12:01









      Michael Rozenberg

      111k1897201




      111k1897201










      asked Mar 24 at 11:38









      Lê Thành ĐạtLê Thành Đạt

      47313




      47313






















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          $begingroup$

          $$measuredangle ECB'=measuredangle AC'B'=measuredangle AE'B',$$ which says that $EE'B'C$ is cyclic.



          Id est, $$AD'cdot AD=AB'cdot AC=AE'cdot AE$$ and we are done!






          share|cite|improve this answer









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            $begingroup$

            $$measuredangle ECB'=measuredangle AC'B'=measuredangle AE'B',$$ which says that $EE'B'C$ is cyclic.



            Id est, $$AD'cdot AD=AB'cdot AC=AE'cdot AE$$ and we are done!






            share|cite|improve this answer









            $endgroup$


















              3












              $begingroup$

              $$measuredangle ECB'=measuredangle AC'B'=measuredangle AE'B',$$ which says that $EE'B'C$ is cyclic.



              Id est, $$AD'cdot AD=AB'cdot AC=AE'cdot AE$$ and we are done!






              share|cite|improve this answer









              $endgroup$
















                3












                3








                3





                $begingroup$

                $$measuredangle ECB'=measuredangle AC'B'=measuredangle AE'B',$$ which says that $EE'B'C$ is cyclic.



                Id est, $$AD'cdot AD=AB'cdot AC=AE'cdot AE$$ and we are done!






                share|cite|improve this answer









                $endgroup$



                $$measuredangle ECB'=measuredangle AC'B'=measuredangle AE'B',$$ which says that $EE'B'C$ is cyclic.



                Id est, $$AD'cdot AD=AB'cdot AC=AE'cdot AE$$ and we are done!







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Mar 24 at 12:00









                Michael RozenbergMichael Rozenberg

                111k1897201




                111k1897201






























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