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Worksheet
Curated OER

Construct, Bisect, Duplicate: Geometry Practice with Compass and Straight Edge

For Students 9th - 12th
Geometers employ a straight edge and compass to duplicate and bisect segments and angles, construct perpendiculars, parallel lines, figures, and circles with points of concurrency. Ample practice with 65 questions across 8 worksheets. No...
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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

Concurrent Lines, Medians and Altitudes

For Students 9th - 10th
In this geometry worksheet, students construct angles and identify medians and altitudes. They use a compass and protractor to perform heir construction. There are 28 questions.
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Worksheet
Curated OER

Lesson 5.3 Vocabulary Quiz: Concurrent Lines, Medians, & Altitudes

For Students 10th - 12th
In this vocabulary worksheet, students match a given vocabulary word to the correct definition.  Words include such terms as altitude, centroid, circumcenter, circumscribed circle, inscribed circle, median and orthocenter.  This one-page...
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Worksheet
Curated OER

Take Home Question

For Students 9th - 12th
In this slope and perpendicular lines worksheet, students solve 5 short answer problems. Students find an unknown coordinate given two points, a perpendicular line, and a slope. Students find the centroid of a triangle.
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Worksheet
Curated OER

Concurrence

For Students 10th
In this concurrence worksheet, 10th graders solve 10 different problems related to determining various concurrences. First, they determine which type of triangle has two altitudes outside of it. Then, students determine the distance...
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Lesson Plan
EngageNY

Special Lines in Triangles (part 2)

For Teachers 9th - 10th Standards
Medians, midsegments, altitudes, oh my! Pupils study the properties of the median of a triangle, initially examining a proof utilizing midsegments to determine the length ratio of a median. They then use the information to find missing...
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Unit Plan
Mathematics Vision Project

Geometric Figures

For Teachers 10th - 12th Standards
Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...
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Worksheet
Curated OER

Concurent Circles II

For Students 9th - 11th
For this geometry worksheet, students draw a shape based on the directions. They tell the reasons the four resulting circles are concurrent. A sample drawing is included.
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Lesson Plan
Curated OER

Circumcenter of a Triangle

For Teachers 9th - 12th Standards
Your geometry learners will discover and show the construction of the circumcenter of a triangle. Guided by the steps in the activity, they construct perpendicular bisectors of each side that have a point of concurrency called the...
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Lesson Plan
Curated OER

NUMB3RS Activity: Regular Ploygon Centroids

For Teachers 9th - 10th
Students investigate geo-profiling.  In this secondary mathematics instructional activity, students use geo-profiling to determine the most probable location of a criminal.  Students find the centroid of a polygon where the vertices...
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Lesson Plan
Curated OER

Bisectors of Triangles

For Teachers 10th
In this geometry worksheet, 10th graders solve problems involving the perpendicular bisectors and angle bisectors of a triangle and their points of concurrency.  The one page worksheet contains sixteen questions.  Answers are included. 
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Lesson Plan
Curated OER

Incenter of a Triangle

For Teachers 10th
Tenth graders find the incenter of a triangle. In this geometry activity, 10th graders define the way to create an incenter with an angle bisector. They differentiate between incenter and incircle.
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Unit Plan
Mathematics Vision Project

Circles: A Geometric Perspective

For Teachers 10th - 12th Standards
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
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Lesson Plan
Curated OER

The Search for Pythagoras' Treasure

For Teachers 8th - 10th
Learners identify and define properties of triangles. In this geometry lesson, students identify the missing sides and angles of right triangles. They use the rules of the Pythagorean Theorem to solve their problems.
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Unit Plan
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EngageNY

Congruence, Proof, and Constructions

For Teachers 8th - 10th Standards
This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons is broken...
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Lesson Plan
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Illustrative Mathematics

Placing a Fire Hydrant

For Teachers 9th - 10th Standards
Triangle centers and the segments that create them easily become an exercise in memorization, without the help of engaging applications like this lesson. Here the class investigates the measure of center that is equidistant to the three...