Archive for the ‘Quadrilateral’ Category

## Quadrilateral Problem

January 7, 2013
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In quadrilateral ABCD with diagonals BD and CA, Read more…

Categories: Quadrilateral
Angle, angles, geometry, quadrilateral

## Quadrilateral & Circle problem

October 1, 2011
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Quadrilateral ABCD is inscribed in a circle. Let AB = a, BC = b, CD = c, DA = d, AC = p and BD = q. Prove Ptolemy’s second theorem that .

This question is also taken from Bertley Math Circle .

It is easy question, just use a, b, c are sides of triangle and S is area of triangle.

If you couldn’t prove send me mail, and i will give few tips.

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Categories: Circles, Quadrilateral
circle, Ptolemy, quadrilateral, triangle