Handout
Math Open Reference

Math Open Reference: The Incenter of a Triangle

For Students 9th - 10th
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.
Whiteboard
ClassFlow

Class Flow: Triangle Segments

For Teachers 9th - 10th Standards
[Free Registration/Login Required] In this flipchart, students use the interactive features of Activstudio to understand how to use the properties of perpendicular bisectors, angle bisectors, medians and altitudes of a triangle.
Unit Plan
Cuemath

Cuemath: Point of Concurrency

For Students 9th - 10th
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.
Lesson Plan
Ministry of Education and Universities of the Region of Murcia (Spain)

Ministerio De Educacion Y Ciencia: Rectas Notables De Un Triangulo

For Teachers 9th - 10th Standards
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.]
Activity
Ministry of Education and Universities of the Region of Murcia (Spain)

Ministerio De Educacion Y Ciencia: Triangulos

For Students 9th - 10th
In Spanish. This interactive activity shows how to compute the area of a triangle and the concept of altitude, median and angle bisector. [Requires Java.]
Handout
Geometry Help

Geometry Help: Isosceles Triangles

For Students 9th - 10th Standards
Explains the basic concept of isosceles triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Activity
Texas Instruments

Texas Instruments: Simple Constructions

For Teachers 9th - 10th Standards
In this skill activity, students can use the Constructions Tools Menu in Cabri Jr. to contruct a parallelogram. They will also construct an altitude, an angle bisector and a median of a triangle.
Activity
Oswego City School District

Regents Exam Prep Center: Concurrence

For Teachers 9th - 10th
Find resources for class instruction on concurrence: a lesson on concurrence of medians, altitudes, angle bisectors, and perpendicular bisectors complete with definitions and example diagrams; a six-question practice quiz; and...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: g.c Inscribing a Circle in a Triangle Ii

For Teachers 9th - 10th Standards
This task focuses on a fact which comes out of the construction of the inscribed circle in a triangle: the angle bisectors of the three angles of triangle ABC all meet in a point. Aligns with G-C.A.3.
Activity
National Council of Teachers of Mathematics

The Math Forum: Problems Library Geometry Triangles

For Students 9th - 10th Standards
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...
Handout
Oswego City School District

Regents Exam Prep Center: Geometry Vocabulary Resources

For Students 9th - 10th
A list of geometry definitions and a matching activity.
Activity
Ministry of Education and Universities of the Region of Murcia (Spain)

Ministerio De Educacion Y Ciencia: Actividades Con Las Rectas De Un Triangulo

For Students 9th - 10th
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.
Activity
Texas Instruments

Texas Instruments: Cabri Geometry Tour

For Teachers 9th - 10th Standards
In this activity, students use the Cabri software to mark points, draw lines, construct parallel and perpendicular lines, angles, bisectors, and triangles. They learn how to use the tool to measure angles.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.6 Theorems Involving Similarity

For Students 9th - 10th Standards
Learn the many theorems about triangles that you can prove using similar triangles.
Handout
CK-12 Foundation

Ck 12: Geometry: Proportionality Relationships Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This study guide looks at proportionality theorems for triangles and parallel lines intersected by transversals.
Handout
Merriam-Webster

Merriam Webster: Dictionary Illustration: Incenter

For Students 9th - 10th Standards
A labeled illustration of an incenter inside a triangle.
Handout
University of Georgia

University of Georgia: Inter Math: Incenter

For Students 9th - 10th
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...
Activity
Texas Instruments

Texas Instruments: Dynamic Geometry: Basic Constructions

For Teachers 6th - 8th Standards
Students use the Cabri Jr. application to draw triangles and construct perpendicular bisectors on the sides of a triangles. They study the properties of a triangle and understand how the measures of angles of a triangle is always 180...
Activity
Texas Instruments

Texas Instruments: Math Today Dangerous Births

For Teachers 9th - 10th
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...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Srt Shortest Line Segment From a Point P to a Line L

For Teachers 9th - 10th Standards
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.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G C Locating Warehouse

For Teachers 9th - 10th Standards
You have been asked to place a warehouse so that it is an equal distance from three roads on a map. Students must fold a paper so that this point is where two folds intersect, and they must explain why their construction works and why...
Handout
Math Words

Mathwords: Inscribed Circles

For Students 9th - 10th Standards
Mathwords provides an explanation and a diagram of an inscribed circle. By clicking on any of the highlighted words, you will learn about related terms.