Wolfram Research
Wolfram Math World: Orthocenter
This site from MathWorld provides a diagram of a triangle with its orthocenter labeled. The site details how to find the orthocenter with links to the key terms. The site details many other interesting properties of the triangle...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Triangle Altitudes
Here at the Math Forum, Dr. Math proves the concurrency of the altitudes of a triangle. Links are provided for associated topics.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Centroid: Center of Gravity
At this site you will find am online discussion about the centroid of a triangle. The page begins with a discussion of observations leading to the centroid of a triangle. Dr. Math explains the correct findings as well as the errors made...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Triangle Centers: Etymologies
At this page you will find Dr. Math responding to an inquiry about the relevance of the names of each of the special triangle centers.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Characteristics of an Orthocenter
Here at The Math Forum, Dr. Math offers interesting properties of orthocenters. Links are provided at the bottom of the page for information on associated topics.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Constructing the Orthocenter
Dr. Math shows how to construct the orthocenter of any triangle using a compass and straight edge.
University of Georgia
University of Georgia: Inter Math: Incenter
This InterMath site gives a description of the incenter of a triangle along with a visual representation. Be sure to follow the links to related terms, everyday examples, challenging problems, and the interactive check point involving...
Wolfram Research
Wolfram Math World: Circumcenter
MathWorld diagrams a triangle with its circumcenter labeled and details how to find the circumcenter with links to the key terms.