
Recent Post – Bài Mới Nhất
 Finite and infinite regions defined by n lines in the plane 10/04/2017
 Using sum of squares triangle to prove sum of squares formula 03/04/2015
 New property of Bui chord circles – Tính chất mới của đường tròn dây cung Bui 06/01/2015
 Proof of Jo Niemeyer’s construction using Kurt Hofstetter’s construction – Chứng minh phép dựng Niemeyer dùng phép dựng Hofstetter 14/12/2011
 Golden Ratio in Parabola – Tỷ Số Vàng trong Parabola 06/12/2011
 Triangle Classification Diagram – Sơ đồ Phân loại Tam giác 01/12/2011
 When I die… 21/11/2011
 Pythagorean Theorem Proof – Chứng Minh Định Lý Pytago 16/08/2009
 Incenters And Golden Ratios In Square 14/03/2009
 Geometrical Object 05/10/2008
 What Is Geometry? 16/09/2008
 Inscribed Heptagon In A Square 11/09/2008
 Magic Rectangle 06/09/2008
 Think Of New One Every Day 04/09/2008
 My Theorem 01/09/2008
 My Favorite Softwares 25/08/2008
 Ba Đường Tròn – Một Lục Giác Nội tiếp 20/08/2008
 Three Circles – One Inscribed Hexagon 20/08/2008
 My Avatar 17/08/2008
 My Favorite Mathematical Websites 17/08/2008
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Tag Archives: triangle
Using sum of squares triangle to prove sum of squares formula
We construct a number triangle from the integers 1, 2, 3, . . . n as follows. The first column contains 2*n1 integers 1. The second column contains 2*n3 integers 2. . . The last column contains only one integer … Continue reading
Posted in Triangle Geometry
Tagged algebra, arithmetics, number, proof, square, sum, triangle
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Golden Ratio in Parabola – Tỷ Số Vàng trong Parabola
Point E is orthogonal projection of focus F on directrix of a parabola. The circle with diameter EF intersects the parabola at two points A, B. Results: Common chord AB divides diameter EF by golden ratio and of course AEF … Continue reading
Posted in Triangle Geometry
Tagged circle, directrix, focus, golden ratio, golden triangle, parabola, tam giác vàng, tỷ số vàng, tiêu cự, triangle, đường chuẩn, đường tròn
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Triangle Classification Diagram – Sơ đồ Phân loại Tam giác
In CTK arcticle Triangle Classification there is one interesting diagram of H. R. Jacobs. In one rectangle it represents all seven kinds of triangles of all classifications. I like it so much. I slightly change it to get one fixed … Continue reading
Magic Rectangle
Draw four horizontal parallel lines from up to down and distances between them are 3, 4 and 5 respectively. Draw four vertical parallel lines from left to right and distances between them are 6, 1 and 8 respectively. Of course … Continue reading
Posted in Triangle Geometry
Tagged altitude, circle, concyclic, euler, magic, nine, orthocenter. midpoint, rectangle, triangle
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Three Circles – One Inscribed Hexagon
I have found this simple method for construction of six concyclic points on sidelines of a triangle on April 6, 2006 and posted in Hyacinthos Geometry Forum. . Detail as following: . Theorem: If three circles concur at one Cevian … Continue reading
Posted in Triangle Geometry
Tagged cevian, circle, concyclic, hexagon, inscribed, triangle
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My Avatar
Dear All My Friends, My Avatar is a image for very simple geometry problem: Given convex quadrilateral ABCD with M, N, P, Q are midpoints of sides AB, BC, CD, DA respectively. Four segments AP, BQ, CM, DN bound one … Continue reading