Question

1.Ptolemy’s Theorem: If ABCD is a cyclic quadrilateral then AB*CD+BC*AD=AC*BD

Answer 1

1.ABCD is a cyclic quadrilateral 1. its given
2. we construct point M on DB a that < ACD=<BCM 2.by construction
this what I have so far

Answer 2

3.<CAD = CD=<CBM 3.<CAD is the subtend arc of CD and <CBM is also the subtend arc of CD
4.triangle DCA~ triangle MCB 4.by similar triangles theorem
5.BC/CM = AC=AC => BC*AD= BC*BM 5. by step 4

Answer 3

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