10 papers
Average Chord Lengths in a Triangle
Stanley Rabinowitz
Let be a point inside a triangle . We consider the average length of the chords of through , where the direction of the chord is chosen uniformly. An elementary formu…
The Probability That the Incenter of a Triangle Lies in a Random Diameter Disk
Stanley Rabinowitz
Let and be independent points chosen uniformly from the interior of a nondegenerate triangle , and let be its incenter. We study the probability that the closed di…
Perspective Central Triangles Formed from a Triangle and a Transversal
Stanley Rabinowitz, Ercole Suppa
Let be a line not passing through any vertex of a triangle and not parallel to any side. Line meets the sidelines , , of at points…
Natural Orderings of Triangle Centers
Stanley Rabinowitz
Triangle centers are usually studied individually or through special geometric relationships, but little attention has been given to global structure among them. In this paper we i…
Some Geometric Properties of the Yff Points of a Triangle
Stanley Rabinowitz, Francisco Javier García Capitán
The Yff points of a triangle were introduced by Peter Yff in 1963. Since then, very few new facts have been discovered about these points. We present some geometrical properties of…
More Shapes of Central Quadrilaterals
Stanley Rabinowitz, Ercole Suppa
Let E be a point in the plane of a convex quadrilateral ABCD. The lines from E to the vertices of the quadrilateral form four triangles. If we locate a triangle center in each of t…
More Relationships between a Central Quadrilateral and its Reference Quadrilateral
Stanley Rabinowitz, Ercole Suppa
The diagonals of a quadrilateral form four associated triangles, called half triangles. Each half triangle is bounded by two sides of the quadrilateral and one diagonal. If we loca…
A Triad of Circles Associated with a Triangle
Ercole Suppa, Stanley Rabinowitz
We study some properties of a triad of circles associated with a triangle. Each circle is inside the triangle, tangent to two sides of the triangle, and externally tangent to the c…
Properties of Ajima Circles
Stanley Rabinowitz, Ercole Suppa
We study properties of certain circles associated with a triangle. Each circle is inside the triangle, tangent to two sides of the triangle, and externally tangent to the arc of a…
Relationships Between Six Incircles
Stanley Rabinowitz
If P is a point inside triangle ABC, then the cevians through P divide triangle ABC into six smaller triangles. We give theorems about the relationship between the radii of the cir…