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Worksheet
Curated OER

Properties of Geometry

For Students 10th
In this properties of geometry worksheet, 10th graders solve and complete 12 different problems that include various theorems. First, they draw a figure that illustrates the SAS inequality property. Then, students prove that two line...
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Activity
Illustrative Mathematics

Tangent to a Circle From a Point

For Teachers 9th - 10th Standards
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using information about...
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Worksheet
Curated OER

More Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve 5 various types of geometry problems related to triangles. First, they draw and label triangles, indicating the additional pairs of corresponding parts that would have to be...
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Worksheet
Curated OER

Identify the Shape

For Students 9th - 10th
10 this geometry worksheet, students identify the different angles created by polygons and name the shape created based on the number of sides. There is an answer key.
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Lesson Plan
Curated OER

Flying with Pythagoras

For Teachers 7th - 10th
A lengthy narrative about Pythagoras and his young scholars precedes an activity in which your young mathematicians practice using the Pythagorean theorem to solve three problems about flight and distance. Answers are provided. 
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Worksheet
Curated OER

Angles and Parallel Lines Homework

For Students 9th - 10th
For this geometry worksheet, students identify the angles formed by parallel lines and a transversal. They differentiate between the angles of a transversal and that of a perpendicular line. There are 14 questions.
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Lesson Plan
Curated OER

Crystals: Geometry and Groups

For Teachers 9th - 10th
Learners discuss the importance of examining crystals and experiment growing them. In groups, they complete a project in which they use groups in geometry just like crystallographers. They practice solving the groups and proofs and...
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Assessment
Inside Mathematics

Rhombuses

For Teachers 9th - 12th Standards
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
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Lesson Plan
Alabama Learning Exchange

Triangle Area: No Height? Use the Sine

For Students 9th - 12th Standards
No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.
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Lesson Plan
EngageNY

Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles

For Students 9th - 10th Standards
Why are right triangles so special? Pupils begin their study of right triangles by examining similar right triangles. Verifying through proofs, scholars recognize the three similar right triangles formed by drawing the altitude. Once...
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Lesson Plan
Virginia Department of Education

Pythagorean Theorem

For Students 8th Standards
Investigate the meaning of the Pythagorean Theorem through modeling. After comparing the area of the square of each side, individuals cut triangles and squares to facilitate the comparison.
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Worksheet
Curated OER

Why do Stars Rise in the East?

For Students 8th - 10th
In this stars rise in the east activity, learners use geometry to show how the Earth rotates from west to east and why celestial bodies appear to rise in the east and set in the west. Students draw a figure and label given points in...
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Lesson Plan
Curated OER

Why Doesn't SSA Work?

For Teachers 10th - 11th
Students investigate the relationship between angles and their sides. In this geometry lesson, students prove why SSA does not work as a true angle side relationship theorem.
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Lesson Plan
Curated OER

Inequalities and Triangles

For Teachers 9th - 10th
Students prove and apply theorems of triangle inequality and hinge theorem. In this geometry activity, students will discuss which triangle is bigger and why. They will use theorems, such as Exterior Angle Inequality or the Pythagorean...
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Worksheet
Curated OER

Challenge: Skills and Applications Lesson 3.4

For Students 9th - 10th
In this geometry worksheet, students identify the missing angles formed by parallel lines and a transversal. They differentiate between parallel and perpendicular lines. There are four questions.
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Lesson Plan
EngageNY

Review of the Assumptions (part 1)

For Students 9th - 10th Standards
What was the property again? Tired of hearing this from your pupils? Use this table to organize properties studied and as a reference tool for individuals. Learners apply each property in the third column of the table to ensure their...
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Lesson Plan
Curated OER

Pythagorean Theorem by Graphic Manipulation

For Teachers 7th - 9th
There are many different ways to show a proof of the Pythagorean Theorem.  Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...
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Lesson Plan
Curated OER

Watch It Slide!

For Teachers 3rd - 5th
Students work together to examine inclined planes. They create a plan to raise rocks to build pyramids. They discover the changes that occur when the angle is increased or decreased.
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Worksheet
Curated OER

Triangle worksheets

For Students 10th
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
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Lesson Plan
Curated OER

Exploring Functions with CAS

For Teachers 9th - Higher Ed Standards
Your mathematicians will examine several conjectures regarding even and odd functions and investigate a formal proof of the conjectures using CAS. 
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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that include various forms of triangles. First, they name the method for proving each set of triangles congruent using the given information....
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Worksheet
Curated OER

If-Then Statements and Postulates

For Students 10th
In this if-then statements and postulates instructional activity, 10th graders solve 6 different problems related to if-then statements and postulates in geometry. First, they identify the hypothesis and conclusion of each conditional...
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Lesson Plan
EngageNY

Prove the Pythagorean Theorem Using Similarity

For Students 9th - 10th Standards
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.
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Lesson Plan
Curated OER

Picking Pythagoras

For Teachers 6th - 9th
Learners discover that side measurement is used in determining angle classification of a triangle. By squaring sides, they predict whether triangles be right, obtuse, or acute. They prove the Pythagorean Theorem and use it to solve...