National Council of Teachers of Mathematics
The Math Forum: Problems Library Geometry Triangles
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...
Other
Gobierno De Navarra: Puntos Y Rectas Notables De Un Triangle
Learn how to construct the bisectors, median and altitude of a triangle.
Calculator Soup
Calculator Soup: Isosceles Triangles Calculator
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
Calculator Soup
Calculator Soup: Right Triangles Calculator
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.
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.
Texas Instruments
Texas Instruments: Simple Constructions With Cabri Jr.
The Cabri Jr. Constructions Tools Menu (F3) contains tools for contructing geometric objects. This activity provides practice using several of the tools. The activity also investigates the terms: median of a triangle and the altitude of...
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Rectas Notables De Un Triangulo
In Spanish. Interactive activities dealing with the concept of angle bisector, median and altitude of a triangle. A description of the circumcenter and centroid are given along with a visual representation. [Requires Java.]
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Triangulos
In Spanish. This interactive activity shows how to compute the area of a triangle and the concept of altitude, median and angle bisector. [Requires Java.]
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Actividades Con Las Rectas De Un Triangulo
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.
Illustrative Mathematics
Illustrative Mathematics: 6.g Same Base and Height, Variation 2
This is the second version of a task asking students to find the areas of triangles that have the same base and height. This presentation is more abstract as students are not using physical models. They still determine the area of each...
Illustrative Mathematics
Illustrative Mathematics: G Srt Ask the Pilot
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...
Math Words
Math words.com: Altitude of a Triangle
This site provides a definition of what the altitude of a triangle is. It also provides a diagram.
Cut the Knot
Cut the Knot: Existence of the Orthocenter
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.
Oswego City School District
Regents Exam Prep Center: Concurrence
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...
Cuemath
Cuemath: Point of Concurrency
Learn all about the point of concurrency. This lesson targets the point of concurrency of perpendicular bisectors, the point of concurrency of the angle bisectors of a triangle, and has interesting solved examples and practice questions.
Homeschool Math
Homeschool Math: Area of Parallelograms
This activity presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
University of Georgia
University of Georgia: Inter Math: Orthocenter
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...
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
Curated OER
Altitudes & Orthocenters: Making Connections...
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.