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.]
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.
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.
Cuemath
Cuemath: Coordinate Geometry
A comprehensive guide for learning all about Coordinate geometry with definitions, the coordinate plane, formulas, equation of a line, related topics, solved examples, and practice questions.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Centroid: Center of Gravity
At this site you will find am online discussion about the centroid of a triangle. The page begins with a discussion of observations leading to the centroid of a triangle. Dr. Math explains the correct findings as well as the errors made...
Wolfram Research
Wolfram Math World: Triangle Median
MathWorld provides an example and explanation for the median of a triangle. Lines A1M1, A2M2, and A3M3 are the medians of triangle A1A2A3.
CK-12 Foundation
Ck 12: Median Centroid
[Free Registration/Login Required] Students will use an interactive triangle to explore how the vertices effect the centroid of the triangle. Click learn more to watch a video and click challenge me to answer a practice question.
Maths Challenge
Maths challenge.net: Triangle Medians
Prove that the centroid, P, splits each median into the ratio 2:1. If you give up, then in the top right corner, you may reveal the solution.
Texas Instruments
Texas Instruments: Centroid and Orthocenter
In this activity, students analyze the location of the centroid and orthocenter for different triangles.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Properties of Triangles
This lesson focuses on the properties of triangles, a closed shape that has three sides, three vertices, and and three internal angles. There are different types of triangles such as a right triangle, obtuse, and acute based on the...
Curated OER
Triangle Medians
MathWorld provides an example and explanation for the median of a triangle. Lines A1M1, A2M2, and A3M3 are the medians of triangle A1A2A3.
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: Baricentro De Un Triangulo
Discover how to find the centroid of a triangle with this interactive activity. [Requires Java.]
Cut the Knot
Cut the Knot!: Napoleon's Theorem
Site that describes in detail Napoleon's theorem. To understand this site be sure you understand what the centroid of an object is. The site describes polygons in terms of the roots of unity of a function. The page gives an interactive...
CK-12 Foundation
Ck 12: Geometry: Medians
[Free Registration/Login may be required to access all resource tools.] Apply the Median Theorem.
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.