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Lesson Plan
Curated OER

Concurrent Lines in Triangles

For Teachers 9th - 12th
Students explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Students use a...
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Worksheet
Curated OER

Points of Concurrency for Triangles

For Students 10th
In this geometry worksheet, 10th graders solve a  problem involving the possible lengths for the third side of a triangle given two sides and determine where the point of concurrency lies in relation to the triangle. The one page...
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Activity
Texas Instruments

Texas Instruments: Centers of a Triangle

For Teachers 9th - 10th
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.]
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Handout
Math Open Reference

Math Open Reference: Centroid of a Triangle

For Students 9th - 10th
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.
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Handout
Math Open Reference

Math Open Reference: Orthocenter of a Triangle

For Students 9th - 10th
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.
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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.
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Handout
Math Open Reference

Math Open Reference: The Circumcenter of a Triangle

For Students 9th - 10th
Learn about the circumcenter 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.