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Lesson Plan
Curated OER

Angles, Triangles, Quadrilaterals, Circles and Related

For Teachers 6th - 8th
Students classify angles. In this angles lesson, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a manipulative...
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Lesson Plan
Curated OER

2-D polygons

For Teachers 3rd - 6th
A hands-on activity uses the Zome modeling system, and helps young geometers either learn or review their knowledge of polygons. Students build as many different 2-dimensional polygons as possible: triangle, square, rectangle, pentagon,...
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Lesson Plan
Curated OER

Types of Triangles

For Teachers 1st - 2nd
Students classify triangles by the length of their sides. In this geometry lesson, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
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Worksheet
Curated OER

Easy Worksheet: Classify the Triangle

For Students 9th - 12th
In this classify the triangle worksheet, students solve 6 short answer problems. Students identify the type of triangle being described according to its angle measures and side lengths.
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Lesson Plan
Curated OER

How many isosceles Triangles Can You Find?

For Teachers 5th
Fifth graders solve problems while examining a variety of isosceles triangles.  In this isosceles triangle lesson, 5th graders examine shapes to find their characteristics.  Students pay particular attention to the characteristics of...
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Worksheet
Math Mammoth

Triangles 1

For Students 5th - 9th
In this triangles worksheet, learners measure and calculate the measurements of eight triangles, their sums and classify the triangles as acute, obtuse or right.
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Worksheet
Curated OER

Triangles

For Students 10th
In 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

Isosceles Triangles

For Teachers K - 2nd
Students investigate triangles. In 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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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...
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Lesson Plan
Curated OER

Geometric Shapes

For Teachers 5th - 7th
Students identify polygons.  In this geometric shape lesson, students explore the characteristics of polygons.  They identify polygons, and classify triangles according to their sides and angles.  Students create a poster representing...
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Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 8th - 10th
Students use the inequality theorem to solve triangles and their properties. In this geometry lesson, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length needed to make a...
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Lesson Plan
Illustrative Mathematics

All vs. Only Some

For Teachers Pre-K - 2nd Standards
All shapes have certain defining attributes that set them apart from others. In order to understand this, young mathematicians look at examples and non-examples of triangles, rectangles, and squares, working as a whole class to create...
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Lesson Plan
Curated OER

Obtuse Triangles

For Teachers 4th
Fourth graders explore obtuse triangles. In this geometry lesson, 4th graders make obtuse triangles with paper and scissors. They determine how to find the center of their triangle.
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Lesson Plan
Curated OER

Equilateral Triangles

For Teachers 4th - 5th
Students examine the attribute of equilateral triangles. In this equilateral triangle lesson, students examine a number of paper triangles to determine how they are classified. They determine how triangles are depicted in Navajo rugs.
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Lesson Plan
Curated OER

Similar and Congruent Triangles

For Teachers 2nd - 4th
Students create and classify different types of triangles using an online geo-board. They explore the concepts of similar and congruent as they discover how to draw similar and congruent triangles.
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Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Students investigate the Pythagorean Theorem. In this geometry lesson, 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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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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Lesson Plan
Curated OER

Triangles Introduction

For Teachers K - 3rd
Students explore geometry by drawing various shapes in class. In this triangle characteristics lesson, students identify the attributes that classify a shape as a triangle and practice using their bodies to create triangles in class....
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Lesson Plan
Curated OER

Angles in Triangles

For Teachers 8th
Eighth graders translate word problems using mathematical ideas. In this geometry lesson, 8th graders identify angles of triangles using equations and the triangle sum theorem. They create angles with a protractor and straight edge.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 9th - 12th
Young scholars are introduced to the Pythagorean theorem. They use three different activities that give students the opportuntiy to observe triangles, and use the Pythagorean theorem and practice different ways of determining areas of...
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Lesson Plan
Curated OER

Roundup Shapes

For Teachers K
Shapes are all around us! Kindergartenrs identify shapes in their world and guess the shape being described. They participate in a shape hunt.
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Worksheet
Curated OER

Special Segments is a Triangle

For Students 10th
In this geometry worksheet, 10th graders examine the special segments that occur in a triangle.  The three page worksheet contains twenty-five problems.  Answers are not included. 
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Lesson Plan
Curated OER

Quandaries, Quagmires, and Quadrilaterals

For Teachers 3rd - 5th
Students classify, flip, slide, and turn a quantity of quadrilaterals.