Pre-K - 2   3 - 5   6 - 8   9 - 12    Across 

Lessons  SWRs  Tools  i-Maths  Inquiry 
Search
Standards
Contact Us
Home
Interactive Math Tools

Interactive Geometry Dictionary
Some Properties of the Angle Bisector

What can you say about the three angle bisectors belonging to a triangle?

In the applet below, the angle bisectors of all three angles of a triangle have been constructed. Drag the vertices to change the triangle. What is always true of the three angle bisectors of a triangle?

Sorry, this page requires a Java-compatible web browser.

Theorem

The three angle bisectors of a triangle all pass through one point. The point of intersection is the incenter of the triangle.


Back to angle bisector

Back to Overview of Lines

References and Credits
National Council of Teachers of Mathematics Illuminating a New Vision for School Mathematics MarcoPolo Education Foundation
Illuminations is a partnership between the National Council of Teachers of Mathematics and the MarcoPolo Education Foundation
© 2000 National Council of Teachers of Mathematics
Use of this Web site constitutes acceptance of the Terms of Use
This page last updated: August 7, 2003


The mission of the National Council of Teachers of Mathematics is to provide the vision and leadership necessary to ensure a mathematics education of the highest quality for all students. The NCTM Illuminations Web site is devoted to providing Internet resources to improve the teaching and learning of mathematics in grades pre-K through 12. The views expressed or implied on this Web site, unless otherwise noted, should not be interpreted as official positions of the Council.