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Instructional Video14:29
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Flipped Math

Addition Postulate

For Students 9th - 12th Standards
Add a little algebra to the geometry. Class members learn about the Addition Postulate for segments and angles. The pupils use their knowledge of solving equations to find lengths of segments and measures of angles. Individuals apply...
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Interactive
CK-12 Foundation

Angle Measurement: Adding Angles

For Students 9th - 12th Standards
Build angles from angles. Using the Angle Addition Postulate, learners find the measures of unknown angles. The interactive simulation shows a visual representation of the postulate and allows individuals to manipulate the angles and...
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Worksheet
Curated OER

Measuring Angles

For Students 10th
In this measuring angles worksheet, 10th graders solve and complete 8 various types of problems. First, they use a protractor to find the measure of each angle shown. Then, students find the missing angle measures. They also refer to the...
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Worksheet
Curated OER

Standardized Geometry Test Practice

For Students 10th
In this angles, lines and figures review worksheet, 10th graders solve and complete 33 standardized multiple choice problems. First, they use the Segment Addition Postulate to solve for a variable given an equation for each line. Then,...
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Lesson Plan
Curated OER

Rays and Angles

For Teachers 9th - 12th
Students view examples of a ray, opposite rays, collinear rays, angles, and straight angles. They discuss and demonstrate how to use a protractor and complete worksheet problems on rays and angles.
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Worksheet
Curated OER

Intersecting Planes

For Students 10th
In this intersecting planes worksheet, 10th graders solve and complete 27 various types of problems. First, they use the diagrams at the right to answer each of the questions. Then, students measure each angle shown and classify them as...
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Worksheet
Curated OER

Verifying Angle Relationships

For Students 10th
In this verifying angle relationships worksheet, 10th graders solve and prove various types of problems related to the verification process of various angle relationships. They complete each of the two proofs shown step-by-step, giving a...
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Lesson Plan
Curated OER

Determining Angle Measure with Parallel Lines

For Teachers 9th - 12th
Students observe and solve examples of corresponding angle postulates, alternate interior angle theorems, and exterior and consecutive angles. They complete the Determining Angle Measure With Parallel Lines worksheet.
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Lesson Plan
Curated OER

Angles and Arcs

For Teachers 9th - 10th
Students discuss the sum of central angles and use string to create them on circles. They find the measure and length of both minor and major arcs. Students give examples of concentric, similar, and congruent circles and congruent arcs.
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Lesson Plan
Curated OER

Measuring Angles & Segments

For Teachers 10th - 12th
Students view a PowerPoint for a warm-up lesson. They practice measuring around the classroom, measuring such things as the length and width of a desk, pencil, door, and book. Students use a website to practice measuring angles.
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Lesson Plan
EngageNY

Triangle Congruency Proofs (part 1)

For Teachers 9th - 10th Standards
Can they put it all together? Ninth graders apply what they know about proofs and triangle congruence to complete these proofs. These proofs go beyond the basic triangle congruence proofs and use various properties, theorems, and...
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Lesson Plan
Curated OER

Triangle Inequality Theorems Investigation

For Teachers 9th - 10th
Students estimate and measure triangles. In this geometry instructional activity, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
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Handout
Lockport City School District

Reasons for Geometric Statement/Reason Proofs

For Students 8th - 11th Standards
Stuck trying to remember the formal language of a geometric proof? Never fear, this handout has them all ready to go. The reasons are sectioned by topic so this handy guide is ready when you are to tackle those two column proofs. 
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Lesson Plan
Virginia Department of Education

Inductive and Deductive Reasoning

For Teachers 9th - 11th
Introduce pupils to the two types of reasoning, inductive and deductive. Classmates work in pairs or small groups to learn the difference between the two and apply these reasonings to develop valid conclusions.