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  1. Encyclopedia of Triangle Centers - Clark Kimberling
    A searchable catalogue of hundreds of special triangle points (centroid, incenter, Hofstadter points, Yff centers, Apollonius point, etc.), with a glossary, collinearities, graphics, and links to biographical sketches of geometers, geometry software and sites, and more. For pictures and constructions of selected cases, see Triangle Centers. more>>

  2. Geometric Formulas (Ask Dr. Math FAQ) - Math Forum
    Formulas for two-dimensional figures: triangle (equilateral, isosceles, right, scalene); quadrilateral (general, square, rectangle, parallelogram, rhombus, trapezoid, kite, cyclic and cyclic-inscriptable); regular polygon; circle (arc, segment, sector); ellipse; parabolic segment; and three-dimensional figures: rectangular parallelepiped (cube); prism; pyramid (square pyramid, frustum); regular polyhedron (tetrahedron, cube, octahedron, dodecahedron, icosahedron); cylinder (right circular); cone (right circular, frustum); sphere (sector, cap, segment, zone, lune); ellipsoid; circular torus; spherical polygon. Includes Defining Geometric Figures. more>>

  3. Mrs. Glosser's Math Goodies - Gisele Glosser
    Interactive math lessons that work online and offline in a Web browser, and provide immediate feedback to students, with in addition Worksheets (on circumference and area; exponents; expressions and equations; integers; Ocean Math; order of operations; percent; perimeter and area; probability; and statistics), Math Chat Boards, Math Puzzles, a Math Image Library, Educational Links, Homework Suggestions, and more. Lessons include examples, exercises, and solutions. Volumes include: Introduction to Statistics; Topics in Pre-Algebra; Probability Lessons; Integers; Understanding Percent; Number Theory; Circumference and Area of Circles; Perimeter and Area of Polygons; and Solutions. These math lessons are shareware and may be used online; registered users may save them to their desktop computers. Leçons en français are also available in French: Théorie des nombres; Circonférence et aire des circles; et Périmètre et aire des polygones. more>>

  4. Naming Polygons and Polyhedra - Math Forum, Ask Dr. Math FAQ
    What do you call an 11-sided polygon? A 14-sided polygon? Is there a list of names of polygons? What about polyhedra? more>>

  5. The Pythagorean Theorem - Math Forum, Ask Dr. Math FAQ
    What is the Pythagorean theorem? When would you use it? How can we prove it? more>>

  6. Quadrilateral Formulas (Ask Dr. Math FAQ) - Math Forum
    Formulas for finding the area, perimeter, etc. of a quadrilateral: square, rectangle, parallelogram, rhombus, trapezoid, trapezium, kite, and cyclic quadrilateral. more>>

  7. Regular Polygon Formulas (Ask Dr. Math FAQ) - Math Forum
    Formulas for finding the area, perimeter, etc. of a regular polygon, and constructing regular polygons with compass and straightedge, in particular the pentagon. more>>

  8. Triangle Centers - Clark Kimberling; Dept. of Mathematics, Univ. of Evansville, Evansville, IN
    A listing, with description and illustration, of 20th-century triangle centers (including: Schiffler Point, Exeter Point, Parry Point, congruent isoscelizers point, Yff Center of Congruence, isoperimetric point and equal detour point, Ajima-Malfatti Points, Apollonius Point, Morley Centers, Hofstadter Points, and equal parallelians points) and some classical triangle centers (including: centroid, incenter, circumcenter, orthocenter, Fermat Point, nine-point center, symmedian (or Lemoine) point, Gergonne point, Nagel point, Mittenpunkt, Spieker center, Feuerbach point, isodynamic points, and Napoleon points), as well as other references (to print works) and a list of journals that frequently publish items of interest to triangle geometers. more>>

  9. Triangle Formulas (Ask Dr. Math FAQ) - Math Forum
    Formulas for finding the area, perimeter, etc. of an equilateral, isosceles, right, or scalene triangle. more>>


Mason error

error in file:   /usr/lib/perl5/5.6.0/Carp/Heavy.pm
line 79:  Bizarre copy of ARRAY in aassign
75:  # them according to the format variables defined earlier in
76:  # this file and join them onto the $sub sub-routine string
77:  if ($hargs) {
78:  # we may trash some of the args so we take a copy
79:  @a = @DB::args; # must get local copy of args
80:  # don't print any more than $MaxArgNums
81:  if ($MaxArgNums and @a > $MaxArgNums) {
82:  # cap the length of $#a and set the last element to '...'
83:  $#a = $MaxArgNums;
component stack:   /library/branch.html
code stack:   /usr/lib/perl5/5.6.0/Carp/Heavy.pm:79

debug info:   Debug file is '/var/lib/mason/debug/anon/15'.


raw error:

error while executing /library/branch.html:
Bizarre copy of ARRAY in aassign at /usr/lib/perl5/5.6.0/Carp/Heavy.pm line 79.