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Worksheet
Curated OER

The Triangles Problem

For Students 10th
In this geometry worksheet, 10th graders explain how two triangles can have 5 parts of the other triangle and still not be congruent. This is a word problem with an answer key.
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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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Unit Plan
Mathematics Vision Project

Module 6: Congruence, Construction, and Proof

For Teachers 8th - 10th Standards
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...
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Assessment
Inside Mathematics

Quadrilaterals

For Teachers 9th - 12th Standards
What figure is formed by connecting the midpoints of the sides of a quadrilateral? The geometry assessment task has class members work through the process of determining the figure inscribed in a quadrilateral. Pupils use geometric...
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Lesson Plan
Utah Education Network (UEN)

Finding Missing Lengths of Similar Triangles

For Teachers 7th - 10th
Middle and high schoolers explore the properties of similar triangles. In this geometry lesson, pupils play a similarity basketball game, sketch similar triangles, and find the missing measures of similar figures. They find the height of...
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Lesson Plan
Curated OER

Finding the Area of an Equilateral Triangle

For Teachers 9th - 11th Standards
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
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Unit Plan
Massachusetts Department of Education

Similarity through Transformations

For Teachers 9th - 12th Standards
Create the ultimate miniature golf course. The 93-page model curriculum unit from the Massachusetts Department of Elementary and Secondary Education contains nine lessons on understanding similarity in terms of both Euclidean geometry...
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Lesson Plan
Willow Tree

The Pythagorean Theorem

For Students 8th - 11th Standards
There isn't a more popular geometry formula than the Pythagorean Theorem! Learners understand the special side relationships in a right triangle. They use the Pythagorean Theorem to find missing sides and to solve problems. They begin...
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Printables
Curated OER

Anticipation Guide: Similar and Congruent

For Students 6th - 8th Standards
Find out what your mathematicians know about similar and congruent figures with this anticipatory guide that includes five agree or disagree with statements.    
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Interactive
Curated OER

Proving Lines Parallel Multiple Choice

For Students 10th - 12th
In this geometry worksheet, students identify parallel lines, examine and interpret diagrams, and find the value of corresponding angles and lines.  This one-page worksheet contains 6 multiple-choice problems.  Answers are...
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Worksheet
Curated OER

List of Geometry Terms

For Students 4th - 9th
In this angle vocabulary card instructional activity 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...
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Unit Plan
EngageNY

Complex Numbers and Transformations

For Teachers 11th - 12th Standards
Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...
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Lesson Plan
Curated OER

Why Does ASA Work?

For Teachers 9th - 10th Standards
Your geometry learners explore Angle-Side-Angle congruence in this collaborative task. The sum of the interior angles of all triangles being one hundred eighty degrees, is the key learners will discover as they explain their reasoning...
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Lesson Plan
Curated OER

Point Reflection

For Teachers 7th - 9th Standards
Use this task as an exit ticket for your eight graders during the geometry unit. All they need to do is identify the coordinates of a point reflected over y=2000. 
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Lesson Plan
Virginia Department of Education

Properties of Quadrilaterals

For Teachers 9th - 11th Standards
What type of quadrilateral is that? Discover the difference between the types of quadrilaterals. Small groups investigate types of quadrilaterals using geometry software to find their properties. To keep track of the different...
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Lesson Plan
Curated OER

Geometry

For Teachers 9th - 12th
Students examine how similar triangles have same angle measures.
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Assessment
Inside Mathematics

Circles in Triangles

For Teachers 9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
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Lesson Plan
Curated OER

Triangle Sum Theorem

For Teachers 10th
Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. 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...
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Lesson Plan
Curated OER

Parallelism in Our Everyday World: Parallel Lines and Beyond

For Teachers 9th - 10th
Students broaden their outlook on geometry in their everyday environment. They explore the properties of parallel lines and parallelograms and discover ways to prove the existence of parallel lines and discuss the concept of parallel lines.
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Lesson Plan
Curated OER

Median of a Trapezoid

For Teachers 8th - 10th
Students find the median of trapezoids and other polygons. In this geometry instructional activity, students identify important properties of trapezoids. They create trapezoids and polygons using Cabri software.
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Lesson Plan
Curated OER

Constructing Parallel and Perpendicular Lines

For Teachers 7th - 9th
 In this geometry worksheet, students construct lines that are parallel and perpendicular forming different angles. They differentiate between interior and exterior angles. Students identify the angles formed by a transversal and...
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Lesson Plan
EngageNY

Informal Proof of AA Criterion for Similarity

For Teachers 8th Standards
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 16 different types of problems. First, they name the corresponding parts of the congruent triangles shown and draw a picture. Then, students list the five ways to...
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Lesson Plan
Curated OER

Congruent Trianges - Is This Enough Information?

For Teachers 7th
Seventh graders determine whether two triangles are congruent and provide an explanation to why they are not. They apply concepts of measurement of angles and collect evidence of congruent angles in the world.