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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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Interactive
CK-12 Foundation

Unit Circle: Medieval Castle Defense

For Students 10th - 12th Standards
Who needs a plan — let trigonometry protect you! Pupils determine the angle of an approaching enemy to a village wall. The scholars determine the exact value of trigonometric functions for the angle. Class members use trigonometry to...
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Worksheet
Curated OER

Similar Polygons

For Students 10th
In this similar polygons worksheet, 10th graders solve and complete 20 various types of problems. First, they solve each proportion. Then, students write a ratio expressing the slope of a line through each pair of points. In addition,...
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Worksheet
Curated OER

Angles ~ Right Angles

For Students 9th - 10th
Have your class review how to identify right angles. Learners identify right angles, and then write the number of angles found in each shape.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 9th - 12th
Learners 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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Worksheet
Curated OER

Triangle: Print and Color

For Students Pre-K - 1st
In this word recognition activity, students trace the word "triangle", write the word independently, and color the picture of the triangle.
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Activity
1
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Curated OER

Mt. Whitney to Death Valley

For Teachers 9th - 12th Standards
This is an intriguing problem that brings together real-world data, technology, and mathematical problem solving. If visibility wasn't an issue, could you see from the highest point in the lower 48 states, Mt. Whitney, to the lowest...
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Lesson Plan
Curated OER

Triangle Congruence

For Teachers 9th - 11th
Students use web applet to create congruent triangles. In this geometry lesson, students differentiate between congruent and similar. They create shapes online and drag those shapes around to create visuals of triangles.
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Lesson Plan
Curated OER

Tennis Triangle

For Teachers 9th - 12th
High schoolers calculate the height of a tree or flagpole. They measure the shadow of the tree or flagpole and the length of a shadow of a meterstick. Using similar triangles, calculate the heigh. Devise two additional ways in which to...
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Worksheet
Curated OER

Triangles

For Students 3rd - 4th
In this triangles learning exercise, students identify 3 triangles by the length of their sides and 3 triangles according to their internal angles.
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Lesson Plan
Curated OER

Similar and Congruent Triangles

For Teachers 2nd - 4th
Learners 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

Obtuse Triangles

For Teachers 4th
Fourth graders explore obtuse triangles. For 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

Similar Triangles

For Teachers 9th
Ninth graders find the height of every day objects using techniques learned through postulates that allow triangles in a problem to be similar. They calculate the length of a missing side and solve proportions.
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Lesson Plan
Curated OER

Similar Triangles - Applied Problems

For Teachers 9th - 12th
Students differentiate between similar and congruent triangles. In this geometry instructional activity, students identify the angles of triangles using the similarity theorem. They apply concepts of triangles to the real world.
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Lesson Plan
Curated OER

Similarity

For Teachers 6th - 8th
Students engage in a lesson that is concerned with the concept of similarity. This takes higher order thinking skills and being able to separate into categories. Specifically in this lesson they are introduced to the scale and how it is...
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Lesson Plan
Curated OER

Identify Similar Figures

For Teachers 6th - 7th
Students explore the concept of similar figures. In this similar figures lesson, students develop the idea that similar figures are a different size but the same shape by comparing similar rectangles. Students use patty paper to trace...
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Worksheet
Houghton Mifflin Harcourt

Similar Polygons and Circles

For Students 9th - 12th
In these similar polygons and circles worksheets, students complete 15 questions including 9 word problems regarding similar polygons. Students then complete 15 questions including 1 word problem involving circumference, area, and arc...
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Lesson Plan
Curated OER

Types of Triangles

For Teachers 5th
Fifth graders explore the required functions of the Geometer's Sketchpad. Using the computer software, they construct similar triangles and identify them by angles and sides. Students classify triangles. Afterward, they complete problems...
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Worksheet
Math Mammoth

Angles in a Triangle 2

For Students 6th - 8th Standards
Youngsters draw specified angles when given measurements of other angles and discover traits of angles in similar triangles. This one-page worksheet contains six multi-step problems.
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Unit Plan
Curated OER

Zome System

For Teachers 4th - 6th
Get hundreds of interactive activity plans using the Zome Modeling System. Among dozens of lessons, a first exposure to similar triangles can be very visual for the learner. Here, young geometers explore the number of different shapes...
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Lesson Plan
Curated OER

Analyzing Congruence Proofs

For Teachers 9th - 12th Standards
Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...
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Handout
Charleston School District

3D Applications of the Pythagorean Theorem

For Students 8th - 10th Standards
How many right triangles can you find in a prism, cone, or pyramid? Using right triangles to find lengths in three-dimensional figures is the focus of the lesson. After working with the Pythagorean Theorem to find missing side lengths...
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Activity
101 Questions

Snail's Pace

For Teachers 6th - 8th Standards
Time doesn't fly when you're watching a snail cross a sidewalk. Combining the concepts of the Pythagorean Theorem and the distance, rate, and time formula, learners determine how long it takes a snail to go from one corner of a sidewalk...
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 9th - 12th
Students identify a right angle and right triangle. They perform WebQuests searching for similar figures and solve for the length of one of the sides given the other two.