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Lesson Plan
Shodor Education Foundation

Triangle Area

For Teachers 6th - 9th Standards
While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...
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Printables
K-5 Math Teaching Resources

Triangle Pack

For Teachers 4th - 6th Standards
With so many different types of triangles, it can be a challenge for young mathematicians to keep them all straight. Luckily this set of printable triangles is here to engage children in comparing and sorting triangles by their...
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Lesson Plan
Curated OER

Exploring Polygons and The Greedy Triangle

For Teachers 1st - 3rd
Excellent lesson! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes), partners form the various shapes...
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Interactive
Shodor Education Foundation

Squaring the Triangle

For Students 8th - 12th Standards
Teach budding mathematicians how to square a triangle with an interactive that shows a graphical proof of the Pythagorean Theorem. Pupils alter the lengths of the legs using sliders. Using the inputted lengths, the applet displays the...
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Worksheet
Mt. San Antonio Collage

Inequalities in a Triangle

For Students 9th - 12th Standards
Stuck with triangle proofs? Take a 180° and provide learners with a guided worksheet that tests their knowledge with triangle inequalities. The questions require different types of proofs that range in levels of difficulty. 
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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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Handout
Mt. San Antonio Collage

Congruent Triangles Applications

For Students 9th - 12th Standards
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the worksheet provides a brief introduction of the different properties and postulates. The remaining pages contain...
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Lesson Plan
Centers for Disease Control and Prevention

Understanding the Epidemiologic Triangle through Infectious Disease

For Teachers 6th - 8th Standards
Introduce infectious diseases and the epidemiologic triangle. A helpful resource describes the agent, host, and environment from the three vertices as well as the time factor, which is in the middle. Scholars complete a simple...
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Lesson Plan
Illustrative Mathematics

Alike or Different Game

For Teachers K Standards
How are a circle and triangle alike? How are they different? These are the types of questions children will answer while playing this fun geometry game. Including a variety of conventional and unconventional shapes, this activity allows...
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Unit Plan
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Mathematics Vision Project

Similarity and Right Triangle Trigonometry

For Teachers 10th - 12th Standards
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
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Lesson Plan
Virginia Department of Education

The Pythagorean Relationship

For Teachers 9th - 11th Standards
Add up areas of squares to discover the pythagorean relationship. Small groups create right triangles with squares along each side. They calculate the areas of each square and notice the relationship. Groups construct other types of...
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Interactive
Shodor Education Foundation

Pythagorean Explorer

For Students 6th - 12th Standards
Make sure the measurement is right. The interactive provides right triangles with a missing side measurement. Pupils use the given sides and the Pythagorean Theorem to calculate the length of the missing side. After entering the length,...
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Printables
Embedded Math

The Unit Circle

For Teachers 10th - 12th Standards
You and your learners will enjoy having a nicely organized, typed up unit circle, all filled in with degrees and radians as well as cartesian coordinates. 
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Lesson Plan
EngageNY

Putting the Law of Cosines and the Law of Sines to Use

For Teachers 11th - 12th Standards
Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...
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Lesson Plan
Curated OER

Symmetries of a Quadrilateral I

For Teachers 9th - 10th Standards
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
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Activity
Teach Engineering

Straw Bridges

For Teachers 6th - 8th
Pairs work as engineering teams to design and build model bridges from drinking straws and tape. In this third segment in a series of 10, teams compete in an attempt to build the strongest bridge. To help with the design, the groups...
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Unit Plan
Mathematics Vision Project

Module 6: Congruence, Construction, and Proof

For Teachers 8th - 10th Standards
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This unit...
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Lesson Plan
Centers for Disease Control and Prevention

Being the “Host” at This Party is No Fun

For Teachers 6th - 8th Standards
Discuss the symptoms and variations from infectious diseases from one person to the next. After a class discussion, small groups complete research on the topic. 
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Unit Plan
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Together Counts

Foundations of Wellness

For Teachers K - 2nd Standards
You may be physically healthy, but what about mentally and emotionally? How is your social health? Kindergartners and first and second graders learn about the importance of maintaining their health in all aspects of their lives with a...
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Lesson Plan
Curated OER

Symmetries of a Quadrilateral II

For Teachers 9th - 10th Standards
Learners investigate the symmetries of a convex quadrilateral in a collaborative activity. Rigid motion and complements are explored as learners analyze different cases of reflections across a line.
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Unit Plan
Calvin Crest Outdoor School

Survival

For Teachers 6th - 12th
Equip young campers with important survival knowledge with a set of engaging lessons. Teammates work together to complete three outdoor activities, which include building a shelter, starting a campfire, and finding directions in the...
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Lesson Plan
Illustrative Mathematics

Sort and Count

For Teachers Pre-K - 1st Standards
Young mathematicians are on their feet and moving around in this primary grade sorting activity. After giving each child an object or picture card, they then sort themselves into groups, counting to see which has the most or least...
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Lesson Plan
Illustrative Mathematics

Make Your Own Puzzle

For Teachers K - 2nd Standards
Puzzling over what geometry activity to teach next? Look no further. This simple activity teaches young mathematicians how shapes can be decomposed into smaller figures, and how smaller figures can be assembled into larger shapes. To...
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Lesson Plan
West Contra Costa Unified School District

Conics Introduction and Parabolas

For Teachers 10th - 12th Standards
Where did conic sections get their name? The equation and graph of a parabola are developed from the definition of the conic section. Teacher examples on graphing the equation and writing an equation from the graph round out the plan.

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