in the diagram below of quadrilateral abcd with diagonal bd

This property of cyclic quadrilateral is known as PTOLEMY THEOREM. 18. Other names for quadrilateral include quadrangle (in analogy to triangle), tetragon (in analogy to pentagon, 5-sided polygon, and hexagon, 6-sided polygon), and 4-gon (in analogy to k-gons for arbitrary values of k).A quadrilateral with vertices , , and is sometimes denoted as . In the diagram below of quadrilateral ABCD with diagonal BD , m