Center Home -> Content Areas Home -> Math Home -> Project Activities -> Sketchpad Activities ->

Exploring Centers of a Triangle: Part 2

Activity Description Activity GuideResources


  • David E. Joyce from the Department of Mathematics and Computer Science at Clark University in Worcester, MA has developed a Geometry applet demonstrating the Euler line of a triangle.
    http://aleph0.clarku.edu/~djoyce/java/Geometry/eulerline.html
  • Clark Kimberling, a Professor of Mathematics at the University of Evansville in Evansville, IN developed a website with various constructions of center points of triangles. Many were developed in the 20th-century, such as:  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, Equal Parallelians Point, Bailey Point. There are also some classical triangle centers constructions: Centroid, Incenter, Circumcenter, Orthocenter, Fermat Point, Nine-point center, Symmedian point, Gergonne point, Nagel point, Mittenpunkt, Spieker center, Feuerbach point, Isodynamic points, and Napoleon points. 
    http://www2.evansville.edu/ck6/tcenters/


  • Key Curriculum Press also has the centroid of a triangle demonstrated on their Java Sketchpad website. 
    http://www.keypress.com/sketchpad/java_gsp/centroid.html

    • Related Articles:

        Baravalle, H. V. (1947). Centroids. Mathematics Teacher, 40, 241-249.

        Court, N. A. (1960). Notes on the centroid. Mathematics Teacher, 53, 33-35.

        Kaner, S. (1964). Discovering the centroid of a quadrilateral by construction. Mathematics Teacher, 57, 484-485.

        Keedy, M. L. (1958). Micky's proof of the medians theorem. Mathematics Teacher, 51, 453-455.

        Koral, I. (1958). A new look at medians. Mathematics Teacher, 51, 123.

        Lightner, J. E. (1975). A new look at the "Center" of a triangle. Mathematics Teacher, 68, 612-615.

        Monroe High School. (1951). The centroid demonstrator. Mathematics Teacher, 44, 138-139.

        Pinker, A. (1980). The method of centroids in plane geometry. Mathematics Teacher, 73, 378-385.

        Satterly, J. (1952). A method for constructing a triangle when the three medians are given. Mathematics Teacher, 45, 602-605.

        Schor, H. (1963). Altitudes, medians, angle bisectors and perpendicular bisectors of the sides of a triangle. Mathematics Teacher, 56, 105-106.

        Shilgalis, T. W. (1972). A transformation proof of the collinearity of the circumcenter, orthocenter and centroid of a triangle. Mathematics Teacher, 65, 635-636.



Back to Project Activities | Back to Math Homepage

Send questions or comments here.
Last modified on June 12, 2002.