{ "id": "1911.01397", "version": "v1", "published": "2019-11-04T18:42:30.000Z", "updated": "2019-11-04T18:42:30.000Z", "title": "Periodic orbits on a 120-isosceles triangle, 60-rhombus, 60-90-120-kite, and 30-right triangle", "authors": [ "Benjamin Baer", "Faheem Gilani", "Zhigang Han", "Ron humble" ], "categories": [ "math.DS" ], "abstract": "A periodic orbit on a frictionless billiard table is a piecewise linear path of a billiard ball that begins and ends at the same point with the same angle of incidence. The period of a primitive periodic orbit is the number of times the ball strikes a side of the table as it traverses its trajectory exactly once. In this paper we find and classify the periodic orbits on a billiard table in the shape of a 120-isosceles triangle, a 60-rhombus, a 60-90-120-kite, and a 30-right triangle. In each case, we use the edge tessellation (also known as tiling) of the plane generated by the figure to unfold a periodic orbit into a straight line segment and to derive a formula for its period in terms of the initial angle and initial position.", "revisions": [ { "version": "v1", "updated": "2019-11-04T18:42:30.000Z" } ], "analyses": { "keywords": [ "straight line segment", "billiard table", "initial angle", "piecewise linear path", "initial position" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }