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Lesson Plan
Curated OER

Proving (a Theorem) and Disproving (a Theory)

For Teachers 7th - 12th
As a cross-curricular lesson, your class examines the issues of gender discrimination, careers, and gender roles. They read and discuss an article, prepare a proof of the Pythagorean theorem as a class, and develop a creative...
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Lesson Plan
EngageNY

Thales’ Theorem

For Teachers 9th - 10th Standards
Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...
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Lesson Plan
Curated OER

Hey, Pythagoras! Help Me Understand Your Theorem!

For Teachers 8th - 12th
Learners explore the Pythagorean Theorem. In this math lesson, pupils solve problems using the Pythagorean Theorem. They select the appropriate numbers to substitute in the formula to solve problems.
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Lesson Plan
EngageNY

Inscribed Angle Theorem and Its Applications

For Teachers 9th - 10th Standards
Inscribed angles are central to the lesson. Young mathematicians build upon concepts learned in the previous lesson and formalize the Inscribed Angle Theorem relating inscribed and central angles. The lesson then guides learners to prove...
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Lesson Plan
West Contra Costa Unified School District

Pythagorean Theorem and Its Converse

For Teachers 9th - 12th Standards
Challenge scholars to prove the Pythagorean Theorem geometrically by using a cut-and-paste activity. They then must solve for the missing sides of right triangles.
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Lesson Plan
Curated OER

Analyzing Congruence Proofs

For Teachers 9th - 12th Standards
Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...
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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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Lesson Plan
Curated OER

Worksheet 5: Property Limits and the Squeeze Theorem

For Teachers 12th - Higher Ed
In this math worksheet, students answer 6 questions regarding given limits in a table of data, properties of limits and the Squeeze Theorem.
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Lesson Plan
EngageNY

Ptolemy's Theorem

For Teachers 9th - 12th Standards
Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.
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Worksheet
Curated OER

Pascal's Theorem

For Students 9th - 12th
In this Pascal's Theorem worksheet, high schoolers prove 1 theorem. Students use GeoGebra to construct lines given three points and prove Pascal's Theorem.
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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
EngageNY

Pythagorean Theorem, Revisited

For Students 8th Standards
Transform your pupils into mathematicians as they learn to prove the popular Pythagorean Theorem. The 16th lesson in the series of 25 continues by teaching learners how to develop a proof. It shows how to prove the Pythagorean Theorem...
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Handout
Charleston School District

Pythagorean Theorem and Converse

For Students 8th Standards
You've heard that it is true, but can you prove it? Scholars learn the Pythagorean Theorem through proof. After an overview of proofs of the theorem, learners apply it to prove triangles are right and to problem solve. This is the second...
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Lesson Plan
EngageNY

Informal Proof of the Pythagorean Theorem

For Students 8th Standards
Prove the Pythagorean Theorem using multiple informal proofs. Scholars first develop an understanding of the origins of the Pythagorean Theorem through proofs. They round out the instructional activity by using the theorem to find...
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Lesson Plan
EngageNY

Converse of the Pythagorean Theorem

For Students 8th Standards
Discover a new application of the Pythagorean Theorem. Learners prove and apply the converse of the Pythagorean Theorem in the 17th lesson in a 25-part series. The examples ask learners to verify right triangles using the converse of the...
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Printables
Mr. Williams Maths

Eight Circle Theorems Page

For Teachers 8th - 12th Standards
Your learners will find these circle theorems nicely organized with diagrams included that present the geometric relationships between the circle circumference, chords, central and circumference angles and tangents.
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Unit Plan
Mathematics Vision Project

Connecting Algebra and Geometry

For Teachers 9th - 10th Standards
Connect algebra and geometry on the coordinate plane. The eighth unit in a nine-part integrated course has pupils develop the distance formula from the Pythagorean Theorem. Scholars prove geometric theorems using coordinates including...
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Instructional Video9:36
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Flipped Math

Proving Lines Parallel

For Students 9th - 12th Standards
Show it can all be proved. Scholars learn the converses of the properties of parallel lines. Using the converses, pupils determine which lines are parallel based on angle measurements and practice using a flow proof to show that two...
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Lesson Plan
Curated OER

The Pythagorean Theorem Lesson 2

For Teachers 8th - 12th
Learners discuss and review examples of the Pythagorean Theorem using a GSP, Geometer's Sketchpad, activity.
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Lesson Plan
Curated OER

Worksheet 5 - Squeeze Theorem

For Teachers Higher Ed
In this Squeeze Theorem worksheet, students compute limits, identify a graph that represents the Squeeze Theorem, and graph given functions. This two-page worksheet contains seven multi-step problems.
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Lesson Plan
EngageNY

Unknown Angle Problems with Inscribed Angles in Circles

For Teachers 9th - 10th Standards
We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson then...
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Lesson Plan
EngageNY

Trigonometry and the Pythagorean Theorem

For Students 9th - 11th Standards
Ancient Egyptians sure knew their trigonometry! Pupils learn how the pyramid architects applied right triangle trigonometry. When comparing the Pythagorean theorem to the trigonometric ratios, they learn an important connection that...
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Worksheet
Curated OER

Proofs Of The Pythagorean Theorem?

For Students 8th Standards
Even U.S. President James Garfield had his own proof of the Pythagorean Theorem! Pupils consider three different attempts at a geometric proof of the Pythagorean Theorem. They then select the best proof and write paragraphs detailing...
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Lesson Plan
EngageNY

Circles, Chords, Diameters, and Their Relationships

For Teachers 9th - 10th Standards
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...