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Lesson Plan
Curated OER

Geometry Journal: Isosceles Triangles

For Teachers 10th - 12th
In this isosceles triangles worksheet, students justify and determine the symmetry of an isosceles triangle. They explore the bisector of rectangles. This three-page worksheet contains two problems. Answers are listed on page three.
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Lesson Plan
National Security Agency

Classifying Triangles

For Teachers 4th - 8th Standards
Building on young mathematicians' prior knowledge of three-sided shapes, this lesson series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The Greedy Triangle,...
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Worksheet
Curated OER

Triangles

For Students 10th
For this triangles worksheet, 10th graders solve and complete 23 various types of problems. First, they match the triangle description with the most specific name and write the letter on the line provided. Then, students classify the...
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Lesson Plan
Curated OER

Classifying Triangles Based On Properties of Angles

For Teachers 5th Standards
The interactive instructional activity featured here calls for the use of a Smartboard for sorting and classifying shapes. Then, pupils discuss the rules they followed for sorting their shapes, particularly focusing on the properties of...
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Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
Learners engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
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Worksheet
Curated OER

Classifying Triangles

For Students 8th - 10th
In this classifying triangles activity, students explore given lengths or angle measurements and then classify each triangle as isosceles, scalene or equilateral. They also determine if the triangle may be right, acute or obtuse. This...
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Worksheet
Curated OER

Triangle Designs

For Students 4th - 6th
In this triangles worksheet, learners draw different triangles and write how many sides and angles each one has. Students draw 4 kinds of triangles and have 2 that are impossible to draw.
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Worksheet
Curated OER

Classify Triangles

For Students 4th - 7th
Here is a classifying triangles practice activity in which learners sharpen their problem solving skills as they solve six story problems.
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Lesson Plan
Curated OER

Triangle Inequality Theorems Investigation

For Teachers 9th - 10th
Students estimate and measure triangles. In this geometry lesson, 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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Lesson Plan
Curated OER

Identifying Angles

For Teachers 4th - 5th
Pupils identify names of angles. They use a large clock to demonstrate angles using certain times of day. Given a geoboard, students create figures with acute, right, and obtuse angles.
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Lesson Plan
Digging Into Math

Classifying Triangles

For Teachers 4th - 8th Standards
Young mathematicians explore the world of three-sided shapes in this lesson on the different types of triangles. Starting with a general introduction to classification using Venn diagrams, children learn how to categorize triangles based...
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Lesson Plan
Curated OER

Study Buddies: Classifying Triangles

For Teachers 4th - 5th
In this math worksheet, students analyze an informative chart about the measurement and angles of equilateral, isosceles and scalene triangles. Students then answer 5 questions about classifying triangles.
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Lesson Plan
Curated OER

The Greedy Triangle-Intro to Geometric Shapes

For Teachers 4th - 6th Standards
 In this geometry lesson, learners read The Greedy Triangle and use geoboards to construct geometric shapes. They identify the number of sides and angles each shape has.
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Worksheet
Mt. San Antonio Collage

Isosceles Triangles and Special Line Segments

For Students 9th - 12th Standards
Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...
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Lesson Plan
Curated OER

Triangles

For Teachers 6th - 10th
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
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Worksheet
Curated OER

Classifying Triangles

For Students 6th
In this classifying triangles instructional activity, 6th graders write the type of triangle, acute, right or obtuse, for 9 pictures of triangles, answers included.
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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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Handout
Charleston School District

Parallel Lines Cut by a Transversal

For Students 8th Standards
Pupils study angle measurements between different types of angles associated with parallel lines and transversals. The independent practice asks pupils to identify the types of angles in a diagram and to determine the measure of angles. 
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Lesson Plan
Curated OER

What are the Kinds of Triangles?

For Teachers 5th
Fifth graders classify triangles. In this triangle lesson, 5th graders learn about the characteristics that make up a triangle. They are instructed through video, PowerPoint slides, and teacher-led demonstrations.
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Lesson Plan
Curated OER

Triangles

For Teachers 4th
Fourth graders participate in three experiments to gain understanding of triangles. In this triangles lesson, 4th graders use pipe cleaners to create bubble pipes, basketball hoops and bingo cards to display the characteristics of...
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PPT
Curated OER

Classifying Triangles

For Teachers 5th - 7th
This presentation shows how triangles are classified by angle measurement and length of sides.  It reviews isosceles, scalene, obtuse, right, and acute classifications and includes questions for students to classify some of the triangles...
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Worksheet
Curated OER

Constructions and Angles

For Students 6th - 10th
In this triangle constructing and classifying worksheet, students read through a tutorial on triangles and angles. Then, students complete 17 exercises in which they answer questions about angles and triangles. By clicking on the "Check"...
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Unit Plan
PBS

Accessible Shapes

For Teachers 6th - 8th Standards
All the 2-D and 3-D measurement work you need is in one location. Divided into three sections, the geometry lesson plans consist of visualization of three dimensions, classifying geometric figures, and finding surface area and volume....
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Lesson Plan
Curated OER

Exploring Geometric Figures

For Teachers 10th
Tenth graders explore mathematics by participating in hands-on daily activities. Learners identify a list of different shapes and classify them by shape, size, sides and vertices. They utilize tangrams and geometric pieces to gain an...