TOPICS

Algebra Applied Mathematics Calculus and Analysis Discrete Mathematics Foundations of Mathematics Geometry History and Terminology Number Theory Probability and Statistics Recreational Mathematics Topology

Alphabetical Index New in MathWorld

Geometry
Plane Geometry
Triangles
Triangle Properties

Geometry
Plane Geometry
Polygons

Petr-Douglas-Neumann Theorem

See

Petr-Neumann-Douglas Theorem

About MathWorld
MathWorld Classroom
Contribute
MathWorld Book
wolfram.com

13,226 Entries
Last Updated: Wed Dec 18 2024
©1999–2024 Wolfram Research, Inc.
Terms of Use

wolfram.com
Wolfram for Education
Created, developed and nurtured by Eric Weisstein at Wolfram Research

Created, developed and nurtured by Eric Weisstein at Wolfram Research