Outline Mathematics
Geometry

Existence of the Circumcenter

This is Euclid IV.5.

 

This applet requires Sun's Java VM 2 which your browser may perceive as a popup. Which it is not. If you want to see the applet work, visit Sun's website at http://www.java.com/en/download/index.jsp, download and install Java VM and enjoy the applet.


Bisect the straight lines AB and AC at the points N and M. Draw the perpendicular bisectors to AB and AC. (The two may meet within the triangle ABC, or on the side BC, or outside BC.)

Let O be the point of intersection. Join O to A, B, C. Since the perpendicular bisector of a line segment is the locus of points equidistant,equidistant,on two sides,equivalent from the endpoints,midpoints,endpoints of the segment, AO = CO and also AO = BO. (By transitivity,commutativity,associativity,symmetry,transitivity, BO = CO.) The three distances are equal and each can be taken as the radius of the circle centered at O. Such a circle, passes through all three vertices,vertices,centers,midpoints of ΔABC. This circle is said to be the circumcircle of the triangle and its center O is known as the circumcenter.


Related material
Read more...

  • Construction of the Angle Bisector
  • Construction of the Perpendicular Bisector
  • |Up| |Contact| |Front page| |Contents| |Geometry| |Eye opener| |Store|

    Copyright © 1996-2012 Alexander Bogomolny

     40619939

    A math books store at a unique math study site. Shopping at the store helps maintain the site. Thank you.
    Sites for teachers
    Sites for parents
    Terms of use
    Awards
    Interactive Activities

    CTK Exchange
    CTK Wiki Math
    CTK Insights - a blog
    Math Help
    Games & Puzzles
    What Is What
    Arithmetic
    Algebra
    Geometry
    Probability
    Outline Mathematics
    Make an Identity
    Book Reviews
    Stories for Young
    Eye Opener
    Analog Gadgets
    Inventor's Paradox
    Did you know?...
    Proofs
    Math as Language
    Things Impossible
    Visual Illusions
    My Logo
    Math Poll
    Cut The Knot!
    MSET99 Talk
    Old and nice bookstore
    Other Math sites
    Front Page
    Movie shortcuts
    Personal info
    Privacy Policy

    Guest book
    News sites

    Recommend this site

    Sites for parents

    Education & Parenting

    Search:
    Keywords:

    Google
    Web CTK
    Supported by
    3wVentures