Wolfram Research
Wolfram Math World: Triangle Centroid
This site from MathWorld gives a diagram of a triangle with its centroid labeled. The site details how to find the centroid with links to the key terms. The site details many other interesting properties of the triangle centroid.
Wolfram Research
Wolfram Math World: Incenter
MathWorld diagrams triangle with its incenter labeled and details how to find the incenter with links to the key terms. The site details many other interesting properties of the triangle incenter.
Texas Instruments
Texas Instruments: Numb3 Rs: Slippery Paths
Based off of the hit television show NUMB3RS, this lesson introduces students to Steiner Points, which are essentially points of concurrency within triangles. This is done in the context of a criminal who needs to place a hideout...
Texas Instruments
Texas Instruments: Circumcenter and Incenter
In this activity, students examine the location of the circumcenter and incenter for different triangles.
Texas Instruments
Texas Instruments: Numb3 Rs: Location! Location! Location!
Based off of the hit television show NUMB3RS, this lesson introduces students to Voronoi diagrams, which split a plane into regions corresponding to distances to given points. The lesson is framed in the context of splitting a city into...
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: 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.
Maths Challenge
Maths challenge.net: Right Time
You will need to do some visualizing to solve this "Right Time" problem. Have fun!
CK-12 Foundation
Ck 12: Geometry: Angle Bisectors in Triangles Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students properties of angle bisectors and how to apply them.
CK-12 Foundation
Ck 12: Geometry: Medians
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the properties of medians and how to apply them.
CK-12 Foundation
Ck 12: Geometry: Proportions With Angle Bisectors
[Free Registration/Login may be required to access all resource tools.] Apply the fact that an angle bisector divides a triangle proportionally.
CK-12 Foundation
Ck 12: Geometry: Proportions With Angle Bisectors
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to set up and solve proportions with angle bisectors.
Merriam-Webster
Merriam Webster: Dictionary Illustration: Incenter
A labeled illustration of an incenter inside a triangle.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Proving the Existence of the Centroid
At this site you will find the proof of the existence of the centroid for any triangle.
Other
Center for Technology and Teacher Education:centers of Triangles Lesson Part Two
This is the second of two consecutive lesson plans concerning the centers of a triangle. The lesson requires the use of Geometer's Sketch Pad. The lesson contains real world applications of some of the concurrent points of a triangle.
Other
Center for Technology and Teacher Education:centers of Triangles Lesson Part One
This is the first of two consecutive lesson plans concerning the centers of a triangle. The lesson requires the use of Geometer's Sketch Pad. The lesson contains real world applications of some of the concurrent points of a triangle.
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...
CK-12 Foundation
Ck 12: Geometry: Inscribed Similar Triangles
[Free Registration/Login may be required to access all resource tools.] Apply the fact that the altitude of a right triangle creates similar triangles.
CK-12 Foundation
Ck 12: Geometry: Medians
[Free Registration/Login may be required to access all resource tools.] Apply the Median Theorem.
CK-12 Foundation
Ck 12: Geometry: Perpendicular Bisectors
[Free Registration/Login may be required to access all resource tools.] Apply perpendicular bisector properties.
CK-12 Foundation
Ck 12: Geometry: Perpendicular Bisectors
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to construct perpendicular bisectors and use the Perpendicular Bisector Theorem.
Math Open Reference
Math Open Reference: Centroid of a Triangle
A complete reference guide to the centroid of a triangle. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Math Open Reference
Math Open Reference: Orthocenter of a Triangle
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.
Math Open Reference
Math Open Reference: The Incenter of a Triangle
Learn about the incenter 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.