Other
Gobierno De Navarra: Puntos Y Rectas Notables De Un Triangle
Learn how to construct the bisectors, median and altitude of a triangle.
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.
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.]
Wolfram Research
Wolfram Math World: Perpendicular Bisector
MathWorld's definition of a perpendicular bisector, with illustrations to show the different uses of the perpendicular bisector.
Math Planet
Math Planet: Geometry: More About Triangles
Explores triangles and related vocabulary through examples and a video lesson.
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.
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...
Wolfram Research
Wolfram Math World: Circumcenter
MathWorld diagrams a triangle with its circumcenter labeled and details how to find the circumcenter with links to the key terms.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice: Polygons and Area of Plane Figures
Practice using your graphing calculator for measuring and constructing polygons and other plane figures. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under...