This site from InterMath gives a description of the orthocenter of a triangle along with a visual representation. Be sure to follow the links to related terms, everyday examples, challenging problems, more information, and the...

In this activity, students analyze the location of the centroid and orthocenter for different triangles.

Students understand that the orthocenter is the point of concurrence of the three altitudes of a triangle. They construct circumcircles and Feuerbach circles and determine the relationship between them.

Learn about the orthocenter of a triangle with this handy reference guide. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.

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...

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.

Dr. Math shows how to construct the orthocenter of any triangle using a compass and straight edge.

This site defines the altitude of a triangle and gives the standard notation for altitudes of a triangle. The site then goes to list several proofs involving altitudes and orthocenters.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

[Free Registration/Login Required] Students will use the interactive riangle and points to explore altitudes such as the orthocenter. Click learn more to watch a video and click challenge me to answer a practice question.

In this activity, students use the Cabri Jr. tools to draw altitudes in a triangle. They construct a line perpendicular to a given line and through a given point. [Requires Adobe Reader.]

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.

This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.