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Lesson Plan
Curated OER

Indirect Proof and Inequalities in one Triangle

For Teachers 10th
In this geometry worksheet, 10th graders complete an indirect proof and order the sides or angles of a triangle. Also, students determine if a triangle can have sides with the given lengths. The two page worksheet contains twelve...
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Lesson Plan
Curated OER

Inequalities and Triangles

For Teachers 9th - 10th
Students prove and apply theorems of triangle inequality and hinge theorem. In this geometry activity, students will discuss which triangle is bigger and why. They will use theorems, such as Exterior Angle Inequality or the Pythagorean...
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Worksheet
Mt. San Antonio Collage

Inequalities in a Triangle

For Students 9th - 12th Standards
Stuck with triangle proofs? Take a 180° and provide learners with a guided worksheet that tests their knowledge with triangle inequalities. The questions require different types of proofs that range in levels of difficulty. 
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Lesson Plan
Curated OER

Drawing Straws

For Teachers 4th
Fourth graders examine the Triangle Inequality Theorem by investigating possible lengths of the sides of a triangle.
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Lesson Plan
Curated OER

Indirect Proof and Inequalities in One Triangle

For Teachers 10th
In this geometry worksheet, 10th graders order the sides and angles of a triangle and determine the range of the third side of a triangle given the lengths of two sides.  The one page worksheet contains sixteen questions.  Answers are...
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Lesson Plan
Key Curriculum Press

Triangle Inequalities

For Teachers 8th - 11th Standards
Properties about triangles are explored in this lesson. Geometers make conjectures about the length of a triangle's sides, the length of the angles in relation to the length of the sides, and the measure of the exterior angles of a...
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Worksheet
Curated OER

Triangles

For Students 10th
In this geometry worksheet, 10th graders solve problems involving triangular inequality. They apply the proofs and theorem of triangles to solve these problems. There is an overview and one question.
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Lesson Plan
Curated OER

Triangle Sum Theorem

For Teachers 10th
Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two...
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Lesson Plan
Curated OER

I'm So Sorry I Ate Chocolate

For Teachers 6th
Sixth graders investigate the magnitudes of the sides and angles of a triangle. They determine the proof of the Sine Rule before using it to solve triangles. They compare the Sine Rule to the Cosine Rule in this unit of lessons.
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Lesson Plan
Curated OER

Quilt Patch Proof

For Teachers 6th - 10th
Students construct a convincing argument that the same amount of fabric is needed for each color of quilt being made in a specific design. They justify the relationship between vertical angles and the sum of the interior angles. Students
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Worksheet
Curated OER

Properties of Geometry

For Students 10th
In this properties of geometry worksheet, 10th graders solve and complete 12 different problems that include various theorems. First, they draw a figure that illustrates the SAS inequality property. Then, students prove that two line...
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Printables
Virginia Department of Education

High School Mathematics Geometry Vocabulary Word Wall Cards

For Teachers 9th - 10th
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...