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Worksheet
Curated OER

Angles in Polygons

For Students 10th
In this geometry worksheet, 10th graders solve problems involving quadrilaterals using the angle sum of quadrilaterals. They solve for linear pairs, opposite angle theorem and triangular angles. There are 5 questions.
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Worksheet
Curated OER

Logical Relationship of Postulates & Theorems

For Students 10th - 12th
In this postulates and theorems worksheet, students explore a concept map containing information about angles and sides, alternate interior angles, and diagonals of a parallelogram.  They use the concept map to prove theorems...
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Lesson Plan
Curated OER

Polygons All Around Us!

For Teachers 9th - 12th
Students explore the concept of polygon properties. In this polygon properties lesson plan, students draw polygons with different numbers of sides such as pentagons, octagons, hexagons, etc. Students identify different geometric shapes...
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Instructional Video
Khan Academy

Khan Academy: Geometry: Corresponding Angle Equivalence Implies Parallel Lines

For Students 9th - 10th Standards
Proof by contradiction that if two lines cut by a transversal create congruent corresponding angles then the lines are parallel. [5:18]
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Instructional Video
Khan Academy

Khan Academy: Geometry: Angles of Parallel Lines 2

For Students 9th - 10th Standards
Explains how to determine the measures of all the angles formed when parallel lines are cut by a transversal based on the measure of one angle. Explains how to use corresponding congruent angles to determine if lines cut by a transversal...
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Instructional Video
Khan Academy

Khan Academy: Parallel Lines & Corresponding Angles Proof

For Students 9th - 10th
Proof by contradiction that corresponding angle equivalence implies parallel lines.
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Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: More Proofs

For Students 9th - 10th Standards
Demonstrates solutions to problems #7-10 of California Geometry released state test questions. Problems address understanding of congruent angle pairs when parallel lines are cut by a transversal, counterexamples, and properties of the...
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Instructional Video
Khan Academy

Khan Academy: Geometry: Proof Sum of Measures of Angles in a Triangle Are 180

For Students 9th - 10th
Proof that the sum of the angles in a triangle is 180 using the relationship of angles formed when parallel lines are cut by a transversal. This video also appears in the Geometry: Triangles strand. [6:31]
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Activity
Texas Instruments

Texas Instruments: Angle Sum in Triangles Proof: Rotation and a Parallel Line

For Teachers 9th - 10th Standards
This investigation uses Cabri Jr. and a cleaver rotation of a triangle to "prove" that the angles in a triangle add up to 180. This could be used to reinforce triangles and paralled lines as well as introduce the concept of rotating an...
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Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Angles of Parallelogram Congruent

For Students 9th - 10th Standards
This video tutorial demonstrates how to prove that the opposite angles of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal. [4:08]
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Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Diagonals of Parallelogram Bisect Each Other

For Students 9th - 10th Standards
Demonstrates how to prove that the diagonals of a parallelogram bisect each other based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [9:06]
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Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Sides of Parallelogram Congruent

For Students 9th - 10th Standards
Demonstrates how to prove that the opposite sides of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [8:30]
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Instructional Video
Study Pug

Study Pug: Perpendicular Line Proofs

For Students 9th - 10th Standards
Video lesson explains angles, lines, and transversals. [9:33]
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Instructional Video
Khan Academy

Khan Academy: Proof Vertical Angles Are Equal

For Students 9th - 10th Standards
Proving that vertical angles are equal
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Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: Pythagorean Theorem, Compass Constructions

For Students 9th - 10th Standards
This video tutorial demonstrates solutions to problems #51-55 of the California Geometry released state test questions. Problems address proving and using the Pythagorean theorem and compass constructions. [12:35]

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