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Organizer
Curated OER

Properties of Shapes

For Students 9th - 12th
In this math worksheet, students look for the properties related to each shape and then fill in the graphic organizer with the categories needed.
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Lesson Plan
Curated OER

Creature Design

For Teachers 5th
Fifth graders create mathematical creatures. In this geometry activity, 5th graders create a creature from regular and irregular geometric shapes. Students review vocabulary and construct an original creature based on a rubric.
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Lesson Plan
Curated OER

Pass It On

For Teachers 5th
Fifth graders participate in a class activity that helps them learn some geometric terms along with their definitions. They describe relationships between two and three-dimensional shapes and analyze attributes and properties of...
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Unit Plan
National Council of Teachers of Mathematics

The Math Forum: Triangle Formulas

For Students 9th - 10th
Investigate the geometric definitions of triangles, focusing upon equilateral, isosceles, right, and scalene with detailed drawings and appropriate formulas for each. This site has links to more information on triangles.
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Activity
Texas Instruments

Texas Instruments: Isosceles Triangle

For Teachers 9th - 10th Standards
In this activity, students construct isosceles and equilateral triangles. They discover that if two sides of a triangle are congruent, then the angles opposite them are congruent. They understand that an equilateral triangle is also...
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Handout
Math Open Reference

Math Open Reference: Isosceles Triangle

For Students 9th - 10th Standards
A reference guide to isosceles triangles. It provides a definition and interactive animated activity that enhances further explanation. Includes links to related topics.
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Unit Plan
Wolfram Research

Wolfram Mathworld: Isosceles Triangle

For Students 9th - 10th
MathWorld explains what an isosceles triangle is and how it compares with equilateral, and scalene triangles. The altitude and area of these triangles are also discussed.
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Lesson Plan
Oswego City School District

Regents Exam Prep Center: Angles and Triangles

For Teachers 9th - 10th Standards
On this site a viewer can learn about the different types of triangles, and categorized by either angles or sides. Tutorials are also included for interior and exterior angles of triangles. A teacher resource page includes a lesson plan...
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Activity
Beacon Learning Center

Beacon Learning Center: Triangles Side by Side

For Students 3rd - 8th Standards
This comprehensive web lesson describes how to classify triangles by their angle and side measurements. It provides real-world examples and exercises for students to practice the skill.
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Handout
CK-12 Foundation

Ck 12: Geometry: Triangle Relationships Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This study guide reviews terminology for triangles, triangle properties, different types of triangles, and interior and exterior angle theorems.
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Unit Plan
Cuemath

Cuemath: Altitude of a Triangle

For Students 9th - 10th Standards
Explore the world of the altitude of a triangle in this mini-lesson including its definition, altitudes in different types of triangles, formulae, some solved examples, and a few interactive questions for you to test your understanding.
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Lesson Plan
Crayola

Crayola: Exploring Triangles.

For Teachers 9th - 10th
Here's a great geometry activity to display students' knowledge of the different types of triangles. Provides resources and adaptations to supplement this lesson plan. (To access this lesson plan, you must register with Crayola.com....
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Activity
Texas Instruments

Texas Instruments: Is an Equilateral Triangle a Special Case of Isosceles?

For Teachers 6th - 8th
The definition of isosceles triangle can determine whether an equilateral triangle is a special case of an isosceles triangle. Using the Cabri Jr. application, students can get a feel for which definition makes the most sense. Along the...
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Activity
Texas Instruments

Texas Instruments: Constructing Triangles

For Teachers 9th - 10th Standards
This activity focuses on the various ways to construct the different types of triangles such as isosceles, equilateral, right, and right isosceles triangles. Students will begin by constructing triangles based on a minimal definition of...
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Handout
Analyze Math

Analyze Math: Free Math Tutorials: Triangles

For Students 9th - 10th Standards
The geometry tutorial investigates the definitions and properties of triangles. Topics included are isosceles, equilateral, and right triangles. In addition, the sine and cosine laws of triangles are defined.
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Unit Plan
CK-12 Foundation

Ck 12: Elem Math: Classifying All Types of Triangles by Lengths of Sides

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying triangles based on length of sides.
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Unit Plan
CK-12 Foundation

Ck 12: Elem Math: Classify Triangles, Composite Figures Number of Equal Sides

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying a triangle inside a composite figure.
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Handout
Quia

Ixl Learning: Types of Triangles

For Students 3rd - 5th Standards
Brush up on your math skills relating to the types of triangles then try some practice problems to test your understanding.
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eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 1.4 Triangles

For Students 9th - 10th Standards
Explore and measure a variety of triangles.
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Lesson Plan
PBS

Pbs Learning Media: Triangles: Targeted Math Instruction

For Students 9th - 10th Standards
Students will learn how to apply the properties and characteristics of all triangles to solve real-world problems and identify and use the unique characteristics of right, isosceles, equilateral, acute, obtuse, and scalene triangles.
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Handout
Geometry Help

Geometry Help: Equilateral Triangles

For Students 9th - 10th Standards
Explains the basic concept of equilateral triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
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Unknown Type
Math Open Reference

Math Open Reference: Triangle Quiz

For Students 6th - 8th Standards
Students are assessed on different types of triangles. Definitions of the triangles are included.
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Unknown Type
McGraw Hill

Glencoe Mathematics: Online Study Tools: Triangles and Angles

For Students 9th - 10th Standards
This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of triangles and angles.
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Activity
AAA Math

Aaa Math: Types of Triangles Based on Sides

For Students 3rd - 5th Standards
Students can practice classifying triangles based on side lengths through a series of self-check exercises and timed learning games.