Ptolemy's Theorem states that the product of the diagonals of a cyclic quadrilateral (a quadrilateral that can be inscribed in a circle) is equal to the sum of the products of the opposite sides. The authors give a new proof making use of vectors.
Original Publication Source:
Original Publication Date:
Several Variable Calculus
Geometry and Topology
History of Multivariable Calculus
Flag for Digital Object Identifier:
3.3 Mainstream Calculus III, IV