In the extensive monograph [9, p.133] on quadrilateral geometry, the following characterization is attributed to Simionescu. A convex quadrilateral is tangential if and only if its consecutive sides a, b, c, d and diagonals p, q satisfies
In the extensive monograph [9, p.133] on quadrilateral geometry, the followingcharacterization is attributed to Simionescu. A convex quadrilateral is tangential ifand only if its consecutive sides a, b, c, d and diagonals p, q satisfies