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: 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...
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.
University of Georgia
University of Georgia: Inter Math: Incenter
This InterMath site gives a description of the incenter of a triangle along with a visual representation. Be sure to follow the links to related terms, everyday examples, challenging problems, and the interactive check point involving...
Illustrative Mathematics
Illustrative Mathematics: G Srt Shortest Line Segment From a Point P to a Line L
In this task, students develop an understanding that the shortest path from a point to a line always meets the line at a right angle. Aligns with G-SRT.C.8.
Texas Instruments
Texas Instruments: Math Today Dangerous Births
In this activity, using the USA TODAY Snapshot "Dangerous births" students will explore the geometric relationships of triangles using perpendicular bisectors of the sides, bisectors of the angles and medians of the triangle. They will...