12 Jan
Latest at Interactive Mathematics Miscellany
Equilateral triangle is the largest among all inscribed into the same circle
http://www.cut-the-knot.org/triangle/InscribedEquilateral.shtml
arctan(1)+arctan(1/2)+actan(1/3)=π/2,
http://www.cut-the-knot.org/Curriculum/Geometry/ThreeSquares.shtml
arctan(1)+arctan(2)+arctan(3)=π,
http://www.cut-the-knot.org/pythagoras/PaperFolding/arctan123.shtml
Related posts: