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Lesson Plan
Curated OER

The Pythagorean Theorem and Classifying Triangles

For Teachers 9th - 12th Standards
Through the examination of the relationship between the lengths of the sides of a triangles students will learn the classification of triangles (acute, right, or obtuse).
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Interactive
CK-12 Foundation

Pythagorean Theorem to Classify Triangles: Missing Angles

For Students 8th - 12th Standards
Learn to use the Pythagorean Theorem with non-right triangles. Pupils use the interactive to discover the relationship between the lengths of sides for acute and obtuse triangles. They compare the squares of the sides of the triangles to...
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Lesson Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
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Worksheet
Curated OER

Classifying Triangles

For Students 10th
In this classifying triangles worksheet, 10th graders solve 6 different problems related to the classification of triangles either by their angles or by their sides. First, they use a protractor and a ruler to draw triangles using the...
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Worksheet
Curated OER

Classifying Triangles

For Students 10th
In this classifying triangles worksheet, 10th graders solve 9 various problems that classify triangles into categories. First, they refer to the figure shown of an isosceles triangle with two line parallel. Then, students name the sides,...
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Lesson Plan
Curated OER

Geometry Journal: Isosceles Triangles

For Teachers 10th - 12th
In this isosceles triangles worksheet, students justify and determine the symmetry of an isosceles triangle. They explore the bisector of rectangles. This three-page worksheet contains two problems. Answers are listed on page three.
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Lesson Plan
Curated OER

Classifying Triangles by the Length of the Sides Using Cabri Jr.

For Teachers 9th - 12th Standards
Learners follow detailed directions to create triangles on their graphing calculator. In this properties of triangles lesson, they will create triangles on their calculators using the Cabri Jr. application. They then identify three...
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Lesson Plan
Curated OER

Triangle Inequality Theorems Investigation

For Teachers 9th - 10th
Students estimate and measure triangles. In this geometry lesson, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
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Worksheet
Mt. San Antonio Collage

Isosceles Triangles and Special Line Segments

For Students 9th - 12th Standards
Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...
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Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
Learners engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
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Lesson Plan
Curated OER

Triangles

For Teachers 6th - 10th
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
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Worksheet
Curated OER

Easy Worksheet: Classify the Triangle

For Students 9th - 12th
In this classify the triangle worksheet, students solve 6 short answer problems. Students identify the type of triangle being described according to its angle measures and side lengths.
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Worksheet
Math Mammoth

Triangles 1

For Students 5th - 9th
In this triangles learning exercise, students measure and calculate the measurements of eight triangles, their sums and classify the triangles as acute, obtuse or right.
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Worksheet
Curated OER

Triangles

For Students 10th
In this triangles worksheet, 10th graders solve and complete 23 various types of problems. First, they match the triangle description with the most specific name and write the letter on the line provided. Then, students classify the...
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Lesson Plan
Curated OER

Exploring Geometric Figures

For Teachers 10th
Tenth graders explore mathematics by participating in hands-on daily activities. Learners identify a list of different shapes and classify them by shape, size, sides and vertices. They utilize tangrams and geometric pieces to gain an...
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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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Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Students investigate the Pythagorean Theorem. In this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
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Worksheet
Curated OER

Constructions and Angles

For Students 6th - 10th
For this triangle constructing and classifying worksheet, students read through a tutorial on triangles and angles. Then, students complete 17 exercises in which they answer questions about angles and triangles. By clicking on the...
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 9th - 12th
Students 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

Special Segments is a Triangle

For Students 10th
In this geometry worksheet, 10th graders examine the special segments that occur in a triangle.  The three page worksheet contains twenty-five problems.  Answers are not included. 
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Worksheet
Curated OER

Informal Geometry

For Students 8th - 12th
Middle and high schoolers solve and complete 29 various types of problems. First, they match each name with its correct formula. Then, students find the length of the missing side and the distance between the two points given. In...
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Lesson Plan
Curated OER

Fractals

For Teachers 10th - Higher Ed
Students explore the concept of fractals. In this fractal lesson plan, students use applets to explore Koch's Snowflake, Sierpinski's Triangle, and other fractals. Students develop these concepts through exploration and teacher guided...
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Worksheet
Curated OER

Points of Concurrency for Triangles

For Students 10th
In this geometry worksheet, 10th graders solve a  problem involving the possible lengths for the third side of a triangle given two sides and determine where the point of concurrency lies in relation to the triangle. The one page...
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Lesson Plan
Curated OER

Property Lists for Quadrilaterals

For Teachers 9th - 12th
Students establish classifications of shapes by various properties (angles, sides, etc.). They introduce the important properties of common shapes. Students develop an awareness of the wide variety of ways the 2-D shapes can be alike.