This site contains a wealth of problems that deal with the basic definitions of medians, altitudes, angle bisectors, and perpendicular bisectors or the defining characteristics of the different types of triangles. There are also...

A list of geometry definitions and a matching activity.

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.

Use this calculator to find the unknown angles in a right triangle using the Pythagorean Theorem. Once you know the sides you can calculate the perimeter, semiperimeter, area, and the altitudes.

You will find an interactive activity to review the following concepts: altitude, median, angle bisector and points of concurrency in triangles. Five different interactive quizzes are also provided to test your knowledge.

In the July 2013 issue of United Airlines' Hemisphere Magazine, a pilot responded to a question about how far in the distance he could see at different altitudes. The solution involved right triangles, lines of tangency to a circle, and...

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.

Find resources for class instruction on concurrence: a lesson on concurrence of medians, altitudes, angle bisectors, and perpendicular bisectors complete with definitions and example diagrams; a six-question practice quiz; and...

This lesson plan presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.

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 skill activity, students can use the Constructions Tools Menu in Cabri Jr. to contruct a parallelogram. They will also construct an altitude, an angle bisector and a median of a triangle.