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Lesson Plan
Curated OER

Triangle Attributes and Measures

For Teachers 7th
Seventh graders explore the concept of triangles. In this triangles lesson, 7th graders sort triangles according to various attributes such as acute, obtuse, isosceles, or equilateral. Students find the area and perimeter of triangles.
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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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Lesson Plan
Curated OER

Concurrent Lines in Triangles

For Teachers 9th - 12th
Students explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Students use a...
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Lesson Plan
Curated OER

Angles And Triangles

For Teachers 7th
Seventh graders participate in a lesson that is focused upon the concepts of classifying different angles and triangles. They practice classifying triangles according to its kind that includes types of angles, congruence, and vertices....
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Worksheet
Curated OER

Similar Triangles

For Students 10th
In this similar triangles worksheet, 10th graders solve and complete 10 different problems related to determining the sides of similar triangles. First, they write three equal ratios to show the corresponding sides that are proportional....
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Lesson Plan
Curated OER

Slides, Flips. Turns......It's All On A Memory Book Page

For Teachers 4th
Fourth graders use tangram sets to investigate the congruence of shapes. They use congruent shapes to demonstrate the properties of slides, flips, and turns. They complete a math journal entry that describes and illustrates each concept.
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Lesson Plan
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Illustrative Mathematics

Applying the Pythagorean Theorem in a Mathematical Context

For Teachers 7th - 9th Standards
Participants who use this resource will apply the Pythagorean Theorem to show whether or not the shaded triangle inscribed in a rectangle is a right triangle. Once all of the sides on the shaded triangle are found, it is important that...
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Lesson Plan
Futures Channel

Folding Circles

For Teachers 7th - 12th Standards
Students investigate properties of circles. In this geometry lesson, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
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Lesson Plan
Curated OER

As the Bird Flies

For Teachers 7th - 8th
Students investigate the properties of lines and congruent triangle theorems as well as apply geometric properties and relationships to real-world mathematical problems. Given two different scenarios, they examine maps that have been...
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Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve 5 problems that relate to different right triangles. First, they find the values of x and y so that each triangle is congruent to the other. Then, students write a two-column proof...
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Activity
Illustrative Mathematics

Reflections and Isosceles Triangles

For Teachers 9th - 11th Standards
Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The...
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Lesson Plan
Houghton Mifflin Harcourt

Developing the Concept: Triangles and Quadrilaterals

For Teachers 5th - 7th Standards
Exact narrative and examples make this lesson on polygons easy to implement. Through it, your class will learn how to use a protractor and ruler to construct triangles and quadrilaterals according to your directions. Your class will be...
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Lesson Plan
Curated OER

The Centroid of a Triangle

For Teachers 9th - 10th
Young scholars familiarize themselves with the construct and measure menus. They demonstrate how to use the Sketchpad Calculator. They draw a triangle and construct the centroid. They shade in each of the small triangles and measure the...
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Lesson Plan
Curated OER

An Application of Congruence

For Teachers 9th - 10th
Young scholars solve triangles using the properties if congruency. In this geometry lesson, students apply congruent and similar figures to solve real world and math problems. They show they are able to follow instructions.
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Worksheet
Curated OER

Proofs

For Students 10th
In this proofs activity, 10th graders solve and graph 8 different equations. First, they prove that each triangle is either congruent or similar. Then, students use the concept of corresponding parts of congruent triangles to solve each...
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Assessment
Concord Consortium

Divisions

For Students 7th - 12th Standards
Divide and conquer the geometry problem. Young scholars consider how to subdivide triangles into smaller ones that have equal areas. They must apply their knowledge of medians to help accomplish the task.
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Lesson Plan
Curated OER

Proofs of the Pythagorean Theorem

For Teachers 9th - 12th Standards
Working individually and collaboratively, geometers gain a clear understanding of the Pythagorean theorem. They create, explain, and compare proofs of the theorem. Proofs involve areas of trapezoids, squares, and triangles, congruent...
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Activity
Illustrative Mathematics

Is This a Parallelogram?

For Teachers 9th - 12th Standards
If both pairs of opposite sides of a quadrilateral are congruent, is the quadrilateral a parallelogram? This task asks learners to determine the answer and to support their answer with a proof. The resource includes a commentary for...
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Lesson Plan
Curated OER

CSI Investigation of Congruence and Similarity

For Teachers 9th - 12th
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
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Lesson Plan
Curated OER

Congruence with Robot Gobot

For Teachers 8th - 10th
Students identify the properties of solids and polygons. For this geometry lesson, students identify the different measurements of a triangle. They use congruence parts and theorem to prove their answer.
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Worksheet
Curated OER

Proving Figures Congruent

For Students 10th
In this proving figures congruent worksheet, 10th graders solve and complete 11 different problems. First, they determine the additional information needed to prove the triangles congruent. Then, students determine which postulate, if...
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Lesson Plan
Pennsylvania Department of Education

Making Triangles

For Teachers Pre-K - 2nd
Pupils use interactive geoboards to identify simple geometric shapes. In this making triangles lesson plan, students describe the properties associated with geometric shapes. Pupils develop spatial sense and the mathematical meaning of a...
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Lesson Plan
Curated OER

An Introductions to Congruent Polygons

For Teachers 8th - 10th
Learners differentiate between similar and congruent polygons. For this geometry lesson, students define the theorems and reasons for polygons similarity and congruence. They are given pictures and patterns to differentiate and identify.
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Lesson Plan
Curated OER

Constructing Midsegments of Triangles

For Teachers 9th - 10th
Learners construct midsegments. In this geometry lesson plan, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.

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