A Euclidean area theorem via isotropic projection (Q1021308)

Using the model for Laguerre geometry based on the \(3\)-dimensional Minkowski space, the author proves by a series of computations the Area Theorem, a generalization of a property of the arbelos (taken here to be simple closed chain of four cycles) first stated as Proposition 4 in the \textit{Book of Lemmas} by Archimedes. That book's Proposition 14 (the Lemma of the Salinon) is shown to be an easy consequence of the Area Theorem.