Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180 degrees; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.

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Students apply the Pythagorean Theorem and criteria for triangle congruence in a proof...and learn how the ancient pyramids of Egypt were laid out.

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By analyzing other students' work, students will gain an understanding of the features of high-quality proofs while developing habits of mind.

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Students analyze a transformation proof for rigor and learn that a famous theorem means more than "a squared plus b squared equals c squared".

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We use Cavalieri's Principle to analyze racing yacht sails, the face of a deck of cards, and shears...which are used in yet another transformation proof.

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Through a kinesthetic menu activity, students will be able to use congruent triangles to write proofs about special triangles and quadrilaterals.

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In this unit assessment, students will demonstrate their understanding of triangle congruence and proof in a series of multiple choice, open-ended, and proof-based questions.

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Students learn about the different types of triangles, the relationships between the interior and exterior angles of a triangle, and apply their knowledge to numerical problems and constructions.

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This lesson gives students the opportunity to discover the relationship between the sides and angles of a triangle through a hands-on activity.