Curated OER
Medians and Altitudes of Triangles
In this geometry worksheet, 10th graders determine if a given segment is a median or altitude of a triangle and use then find the indicated missing length or equation of a line. The two page worksheet contains twenty problems. Answers...
Curated OER
Regents Exam Questions G.G.21: Centroid, Orthocenter, Incenter, and Circumcenter
In this triangles instructional activity, students solve 4 multiple choice problems. Students find the centroid, orthocenter, incenter, and circumcenter or various triangles.
Curated OER
Exploring the Orthocenter of a Triangle
Young mathematicians explore the concept of triangles as they construct altitudes of triangles to find the orthocenter. Learners construct their triangles using Cabri Jr. on their graphing calculators and find that the altitudes of a...
Curated OER
Properties of the Centers of a Triangle
High schoolers investigate properties of the four centers of a triangle and explore a special property of the circumcenter and orthocenter of a triangle. This lesson requires the use of Cabri, Jr.
Curated OER
Concurrence
In this concurrence worksheet, 10th graders solve 10 different problems related to determining various concurrences. First, they determine which type of triangle has two altitudes outside of it. Then, students determine the distance...
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.
Texas Instruments
Texas Instruments: Centers of a Triangle
The centroid, circumcenter, orthocenter, and incenter are the four classic centers of a triangle that are studied in geometry. In this activity, you will construct these center points and discover their properties. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Centroid and Orthocenter
In this activity, students analyze the location of the centroid and orthocenter for different triangles.
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.
CK-12 Foundation
Ck 12: Geometry: Altitudes Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students properties of altitudes of triangles and how to apply them.
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...
Other
Gobierno De Navarra: Puntos Y Rectas Notables De Un Triangle
Learn how to construct the bisectors, median and altitude of a triangle.
CK-12 Foundation
Ck 12: Geometry: Bisectors, Medians, Altitudes Study Guide
This study guide on bisectors, medians, and altitudes covers key vocabulary, different theorems, and facts about the altitude and triangles. It is available for download with free registration.
Math Open Reference
Math Open Reference: Altitude of a Triangle
Learn about the altitude of a triangle with this handy reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Math Open Reference
Math Open Reference: Euler Line
Learn about the Euler line with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.5 Theorems About Concurrence in Triangles
Find out about some common centers of triangles.
University of Georgia
University of Georgia: Altitudes & Orthocenters: Making Connections
This site describes altitudes and orthocenters in triangles and their connections with the nine-point circle.
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...
Other
University of Evansville: Encyclopedia Triangle Centers
This site contains a comprehensive study of triangle centers. Seems more for an advanced level. Provides a list of six links to 1114 centers.
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: 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.
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.