AB and AC are equal chords of a circle. AD and BE are parallel chords through A and B respectively. Prove that AE is parallel to CD.

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- July 11th 2010, 06:34 PMLukybearCircle Geometry: Difficult Proving Parrallel Lines
AB and AC are equal chords of a circle. AD and BE are parallel chords through A and B respectively. Prove that AE is parallel to CD.

- July 11th 2010, 10:50 PMsimplependulum
Note that if a cyclic quadrilateral is a trapzeium , then it is an isosceles trapzeium . If a pair of the opposite sides are equal in length , then it is also an isosceles trapzeium .

To prove the first line , Let is a cyclic quadrilateral , assume it is a trapzeium , say , then we have so thus it is an isos. trapzeium .

I give the proof of the second line to you .

By applying the above property , we find that so - July 12th 2010, 02:00 AMLukybear
Sorry, I am not so sure ABCD is concyclic. As ABCE is the actual quad inside circle.

EDIT: nvm, i have found solution anywaz.