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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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Interactive
CK-12 Foundation

Ck 12: Isosceles Triangles

For Students 7th - 9th Standards
[Free Registration/Login Required] Students are given an Isosceles triangle and are asked to move the point on the line segment to explore how the angle measure changes. Click learn more to watch a video demonstration and click challenge...
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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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Handout
Oswego City School District

Regents Exam Prep Center: Geometry Vocabulary Resources

For Students 9th - 10th
A list of geometry definitions and a matching activity.
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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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Unit Plan
CK-12 Foundation

Ck 12: Elem Math: Determine Unknown Angles: Isosceles, Scalene, Right Triangles

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on finding the missing angles in triangles.
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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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Unit Plan
CK-12 Foundation

Ck 12: Elem Math: Determining the Length of an Unknown Side of a Triangle

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video tutorial and attempt practice problems on how to determine the unknown side length of a triangle.
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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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Handout
Calculator Soup

Calculator Soup: Isosceles Triangles Calculator

For Students 9th - 10th Standards
Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Classification Grades 8 10

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Classification Grade 7

For Students 7th Standards
[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Classification Grade 8

For Students 8th
[Free Registration/Login may be required to access all resource tools.] Classifying triangles by using angle measures and side lengths.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Classification Grades 9 10

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to classify triangles based on their angles and sides.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Classification by Side Lengths

For Students 6th
[Free Registration/Login may be required to access all resource tools.] Classify different types of triangles by their side lengths.
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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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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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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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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Recognize 45 45 90 Right Triangles

For Students 8th
[Free Registration/Login may be required to access all resource tools.] Recognize special right triangles and their properties.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: 45 45 90 Right Triangles

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] Apply the special properties of 45-45-90 right triangles.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Triangle Sum Theorem Grade 8

For Students 8th
[Free Registration/Login may be required to access all resource tools.] Finding and understanding the angle measures of 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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Activity
Maths Challenge

Maths challenge.net: Tick Tock Triangle

For Students 9th - 10th Standards
This is a "three star" geometry problem where prior knowledge of probability is required to solve this "Tick Tock Triangle" problem, have fun!