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Lesson Plan
Curated OER

Isosceles Triangles

For Teachers 9th - 10th
Students identify the properties of an isosceles triangle. For this geometry lesson, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
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Lesson Plan
Curated OER

Conjectures of Intersecting Circles

For Teachers 9th - 10th
Students make conjectures of intersecting circles. In this geometry lesson, students observe circles and their position in space. They investigate and observe two and three dimensional objects.
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Lesson Plan
Curated OER

Inscribed Angles

For Teachers 9th - 10th
Students calculate the inscribed angle of a triangle. In this geometry lesson, students identify the angle created by intersection of a triangle and a circle. They see the relationship between the arc and the angle.
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Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
Students solve problems using geometric means. In this geometry lesson plan, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
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Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
Student identify the solution using geometric mean. In this geometry instructional activity, students create right triangles where the altitude of the triangle is the side containing the right angle. They modify shapes using Cabri...
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Lesson Plan
Curated OER

Linear and Locomotor Movements

For Teachers 4th - 5th
Students develop locomotor movements. In this dance movement lesson, students identify lines and develop creativity while performing to "Cha Cha Slide". Students discuss how to create dances and difficulty of movements. 
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Lesson Plan
Curated OER

Side Splitter Triangles

For Teachers 8th - 11th
Students investigate the side splitter theorem. In this geometry lesson, students estimate and solve problems dealing with ratios and proportions. They identify angles created by lines that are parallel.
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Worksheet
Curated OER

Geometric Proof and Angles

For Students 10th
In this geometry worksheet, 10th graders write two-column and paragraph proofs to prove angle pair relationships.  The one page worksheet contains five problems.  Answers are not included. 
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Lesson Plan
Curated OER

Exploring the Properties of Rectangular Prisms.

For Teachers 9th - 10th
Students define properties of rectangular prisms. For this geometry lesson, students identify the relationship between two and three dimensional objects. They use Cabri technology to graph their figures.
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Lesson Plan
Curated OER

Exploring Properties of Rectangular Prisms

For Teachers 8th - 10th
Students explore the properties of rectangular prisms. In this geometry lesson, students identify properties of two and three dimensional shapes. They use Cabri technology to create polygons and solve problems.
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Activity
Illustrative Mathematics

Slopes and Circles

For Teachers 9th - 12th Standards
An upper-level treatment of what is often presented as a basic concept (the right angle of an inscribed circle on the diameter), this activity really elevates the mathematical thought of the learner! Expected to develop formulas from...
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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

Geometry House!

For Teachers 4th
Fourth graders use computer drawing tools to create a house of geometric shapes.
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Lesson Plan
Curated OER

Studying Special Segments in Triangles

For Teachers 8th - 10th
Students investigate special segments in triangles. In this geometry lesson, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.
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Lesson Plan
Curated OER

Reflections

For Teachers 5th
Fifth graders create a reflection of a poygon using a Mira. They discover that a line connecting a vertiex of a polygon and the corresponding vertex of its reflection is perpendicular to the line of reflection. Students create a glide...
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Lesson Plan
Curated OER

"Geotown" Scrapbook

For Teachers 3rd - 5th
Students create a scrapbook. In this geometry lesson plan, students use digital cameras to take pictures of geometrical concepts. Students use the pictures to create a "Geotown" scrapbook.
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Lesson Plan
Curated OER

The Search for Pythagoras' Treasure

For Teachers 8th - 10th
Students 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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Lesson Plan
Curated OER

Tangents to a Circle

For Teachers 9th - 10th
Students construct tangent lines. In this geometry instructional activity, students identify the point of tangency, secant and tangent lines. They graph the lines on the Ti and make observations.
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Worksheet
Curated OER

Coordinates Graphing

For Students 9th - 10th
In this geometry activity, students are given points to plot on a coordinate plane. They identify plotted coordinate pairs. There are 10 questions.
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Lesson Plan
Curated OER

Plain Figures and Measuring Figures

For Teachers 10th - 12th
Students investigate basic geometric concepts. In this geometry lesson plan, students explore solids through measuring and modeling. This assignment models the importance of understanding concrete objects in geometry.      
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Lesson Plan
Curated OER

A Lesson on the Root Spiral

For Teachers 9th - 10th
Students create lines and shapes with a compass and a straight edge. For this geometry lesson, students investigate square roots, irrational numbers and spirals. They explore nature to see the shapes representing mathematics and...
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Lesson Plan
Curated OER

Diagonals to Quadrilaterals II

For Teachers 8th - 10th
Students identify the properties of different polygons. In this geometry lesson, students find the slope of a line and calculate the distance between two lines. They differentiate between similar and congruent polygons.
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Worksheet
Curated OER

Triangle Fundamentals Homework

For Students 9th - 10th
In this geometry worksheet, students identify the missing angles of non right triangles using the angle sum theorem. They solve for the unknown using algebra. There are 21 questions.
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Lesson Plan
Curated OER

Diagonals of Quadrilaterals

For Teachers 9th - 10th
Students find the diagonals of the quadrilaterals. In this geometry lesson, students identify and use properties of quadrilaterals. They define different parts of a quadrilateral shape.