Question
Fri February 13, 2009 By:

triangles

Expert Reply
Thu March 05, 2009

Pls check the To Prove statement. It should be BD2-CD2=2CD.AD

Consider L.H.S

BD2-CD2

= AB2-AD2-CD2 (By pythagoras theorem in triangle ABD)

= AC2-AD2-CD2 (As ABC is isosceles triangle where AB=AC)

=(AC+AD)(AC-AD)-CD2

=CD(AC+AD)-CD2

=CD(AC+AD-CD)

=CD.2AD = 2AD.CD

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