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Lesson Plan
Curated OER

Concurrent Lines in Triangles

For Teachers 9th - 12th
High schoolers 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. High...
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Worksheet
Curated OER

Identify Triangles

For Students 5th - 6th
In this triangle worksheet, students identify triangles as either, right, acute, obtuse, equilateral, scalene or isosceles. A reference web site is given for additional activities.
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Worksheet
Curated OER

Identifying Types of Triangles

For Students 5th - 6th
In this triangle learning exercise, students check the appropriate label for triangles: right, acute, obtuse, scalene, isosceles or equilateral. A reference web site is given for additional activities.
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Worksheet
Curated OER

List of Geometry Terms

For Students 4th - 9th
In this angle vocabulary card worksheet set, students identify the vocabulary associated with angles such as: ray, vertex, acute angle, segment bisector, and corresponding angles. They identify 23 terms but there are no questions...
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Lesson Plan
Curated OER

The Pythagorean Theorem

For Teachers 10th
In this geometry worksheet, 10th graders apply the Pythagorean Theorem as they determine the length of the missing leg or hypotenuse in right triangles.  The one page worksheet contains twelve questions.  Answers are included. 
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Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles activity, 10th graders solve and complete 12 different types of problems. First, they solve for a variable given each of the right triangles with the sides as indicated. Then, students determine the shorter...
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Worksheet
Curated OER

Identify Triangles

For Students 3rd - 5th
In thins triangles review worksheet, students examine 3 triangles and their measurements. Students classify them as acute, right, obtuse, equilateral, isosceles, or scalene.
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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 instructional activity series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The...
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Lesson Plan
Curated OER

2-D Geometry

For Teachers 3rd
Third graders are introduced to new vocabulary related to Geometry. As each word is mentioned, they demonstrate the word with their body. In groups, they identify the similarities and differences between each line and angle. To end...
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Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 8th - 10th
Learners 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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Lesson Plan
Curated OER

Triangle Conjectures

For Teachers 10th
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
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Worksheet
Curated OER

Identifying Triangles

For Students 4th - 6th
In this triangle worksheet, students label triangles as acute, right, obtuse, scalene, equilateral or isosceles. A reference web site is given for additional activities.
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Lesson Plan
Curated OER

"Alphabet City and City by Number" by Stephen T. Johnson; "Shapes, Shapes, Shapes" by Tana Hoban

For Teachers 6th - 8th
Students review the definition of angles by identifying those in the classroom and putting them on a graphic organizer.
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Worksheet
Curated OER

Identify Triangles #

For Students 4th - 6th
In this triangle worksheet, students identify triangles as scalene, equilateral, right, obtuse, acute or isosceles. A reference web site is given for additional activities.
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Worksheet
Curated OER

Identify Triangles #3

For Students 3rd - 5th
In this triangle worksheet, students identify triangles as obtuse, right, or acute, checking the correct answer. A reference web site is given for additional activities.
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Worksheet
Curated OER

Identify Triangles #2

For Students 5th - 6th
In this triangle worksheet, students identify a set of triangles as either acute, right or obtuse, checking the appropriate box beneath each. A reference web site is given for additional activities.
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Worksheet
Curated OER

Identify Triangles

For Students 4th - 6th
In this triangles learning exercise, students identify triangles as either Acute, right or obtuse. A reference web site is given for additional activities.
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Worksheet
Curated OER

Identify Triangles

For Students 4th - 6th
In this triangle worksheet, students check the correct answer, identifying triangles as either right, obtuse, acute, scalene, isosceles or equilateral. A reference web site is given for additional activities.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 7th - 10th
Students find the different ratios of a triangle. In this geometry lesson, students use the Pythagorean Theorem to solve for missing sides and angles on a right triangle. They use a robot to create a right triangle.
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Worksheet
Curated OER

Triangles

For Students 3rd - 4th
In this triangles worksheet, 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

Types of Triangles

For Teachers 1st - 2nd
Students classify triangles by the length of their sides. In this geometry activity, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
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Worksheet
Curated OER

Easy Worksheet: Types of Triangles

For Students 9th - 12th
In this types of triangles worksheet, high schoolers solve 6 short answer problems. Students identify the type of triangle being described according to side length or angle measure.
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Lesson Plan
Curated OER

Studying Special Segments in Triangles

For Teachers 8th - 10th
Pupils investigate special segments in triangles. In this geometry lesson, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 7th - 8th
Students explore the history of Pythagoras and his contributions to mathematics. In this middle school geometry lesson, students use one inch tiles to investigate the Pythagorean Theorem and to find the length of the sides of a right...