**
Martin Josefsson, The area of a bicentric quadrilateral,
Forum Geometricorum, 11 (2011) 155--164.
**

Abstract. We review and prove a total of nine different formulas for the area of a bicentric quadrilateral. Our main result is that this area is given by K= (m^2-n^2)kl/(k^2-l^2) where m, n are the bimedians and k, l the tangency chords.

[ps file] [pdf]