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Worksheet
Curated OER

Identify Angles: Obtuse, Right, Straight and Acute

For Students 5th - 6th
In this triangle worksheet, students identify angles as either obtuse, right, straight or acute. A reference web site is given for additional activities.
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Worksheet
Curated OER

Independent Practice 2: Triangles

For Students 6th - 8th
In this triangle worksheet, learners identify given triangles according to their sides and angles. Afterward, students draw triangles to match given descriptions. This one-page worksheet contains 15 problems.
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Lesson Plan
Curated OER

Geometry Review

For Teachers 7th
Seventh graders explore basic geometric definitions involving angles, area, and circumference. To reinforce basic geometric concepts, they play a "lightning Flash" card game. Students discuss chores or jobs that require the use of...
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Interactive
CK-12 Foundation

Ambiguous Case: Furniture Store Problems

For Students 10th - 12th
Remove any ambiguity about using a helpful resource. Individuals use an interactive to find the number of triangles that fit given conditions. They find that some conditions can result in more than one triangle in the ambiguous case.
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Lesson Plan
Curated OER

Identify triangles

For Teachers 9th - 10th
Students explore triangles. In this geometry lesson, students will create note cards with pictorial depictions of right, acute,obtuse, scalene, isosceles, equilateral and equiangular triangles. Students will verbally describe each type...
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Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Students investigate the Pythagorean Theorem. In this geometry lesson plan, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
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Interactive
Noetic Learning

Kinds of Triangles (Online Interactive)

For Students 3rd - 4th
In this triangles learning exercise, students analyze pictures of four triangles. For each triangle, students mark if it is acute, obtuse, or right.
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Worksheet
Curated OER

Acute and Obtuse Angles

For Students 3rd - 5th
In this angles instructional activity, students label a set of 4 angles as either acute or obtuse. Page has several links to additional geometry activities.
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Worksheet
Curated OER

Identify Angles: Acute, Right, Obtuse and Straight

For Students 5th - 6th
In this angles worksheet, students identify a set of angles as either acute, right, obtuse or straight. A reference web site is given for additional activities.
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Lesson Plan
Curated OER

Isosceles Triangles

For Teachers K - 2nd
Students investigate triangles. For this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Students locate the prefix "tri" in a variety of words and make connections with...
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Lesson Plan
Curated OER

Triangle Puzzler

For Teachers 5th - 8th
Students are introduced to some basic concepts of geometry. They explain that the definition of a triangle is a figure with three sides, three angles, and three points. Triangles can be named by using three points in their correct sequence.
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Lesson Plan
Curated OER

Classifying and Constructing Corners

For Teachers 5th
Fifth graders, after seeing Honeycomb examples, complete a Classifying Angles worksheet, Clock worksheet, and Defining Angles worksheet.
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Interactive
Curated OER

Identifying Triangles

For Students 10th
In this geometry worksheet, 10th graders identify a triangle as right, acute, or obtuse and identify the parts of a right triangle in a drop and drag game format.  The one page interactive worksheet contains eight matching questions and...
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Lesson Plan
Curated OER

Geoboard Ideas

For Teachers 3rd - 4th
Learners build polygons on their geoboards. In this geometry lesson plan, students build and then draw it on paper and label it. Learners then switch with a partner to try an make a symmetrical shape.
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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

Points, Lines, Planes, and Space

For Teachers 9th - 12th
In this points, lines, planes, and space worksheet, high schoolers solve word problems dealing with points, lines, planes, and space. Students complete 20 individual problems and 20 group problems.
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Worksheet
K12 Reader

Classifying Triangles

For Students 2nd - 3rd Standards
Bring math and reading informational text together with a reading comprehension lesson. After kids read about isosceles, scalene, and equilateral triangles, they answer five comprehension questions to demonstrate how they can use context...
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Lesson Plan
Curated OER

2-D Geometry

For Teachers 3rd
Third graders describe and compare attributes of two-dimensional shapes. They explain geometric terms, angles and shapes. Students demonstrate each vocabulary word with their body and they mirror the body positions associated with each...
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Lesson Plan
Curated OER

Lines and Angles

For Teachers 4th - 5th
Students explore Geometry with Twizzlers Candy, pipe cleaners, paper, pencils, and protractors. They manipulate these items to create different angles introduced by the teacher.
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Worksheet
Curated OER

Downtown Landmarks: geometry on Firstside

For Students 5th - 10th
In this geometry learning exercise, students look at a picture of downtown landmarks and identify different shapes, lines, and more. Students identify 18 items.
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Worksheet
Math Mammoth

Triangles

For Students 6th - 8th Standards
A six-page packet walks, or bends learners through angles that combine to create triangles. Definitions are given for right triangles, obtuse and acute triangles. They draw angles according to directions, using a protractor to meet the...
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Lesson Plan
Curated OER

Contructions and Conjectures

For Teachers 10th - 11th
Students make constructions and conjectures. For this geometry lesson, students construct right, acute and obtuse angles using a straight edge and a protractor. They investigate parallel lines and the angles formed by the angles.
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Lesson Plan
Curated OER

Picking Pythagoras

For Teachers 6th - 9th
Students discover that side measurement is used in determining angle classification of a triangle. By squaring sides, they predict whether triangles be right, obtuse, or acute. They prove the Pythagorean Theorem and use it to solve...
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Lesson Plan
Beacon Learning Center

The Fun Polygon

For Teachers 4th - 6th Standards
Junior geometers use hands-on manipulatives to explore and describe the properties and attributes of a fundamental polygon, the triangle. They learn different kinds of angles and their measurements. This well-written lesson plan provides...