G-SRT.2.4

Prove theorems about triangles. Theorems include: a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem proved using triangle similarity.

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Formative Assessments
Formative Assessments
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Students are asked to prove that if a line intersecting two sides of a triangle divides those two sides proportionally, then that line is parallel to the third side.
Converse of the Triangle Proportionality Theorem
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Students are asked to prove that the length of the altitude to the hypotenuse of a right triangle is the geometric mean of the lengths of the two segments of the hypotenuse.
Geometric Mean Proof
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Students are asked to prove the Pythagorean Theorem using similar triangles.
Pythagorean Theorem Proof
Virtual/Hands-on Manipulatives
Virtual/Hands-on Manipulatives
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Representation to illustrate the Pythagorean Theorem.
Demonstrate the Pythagorean Theorem
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This web address, from the National Library of Virtual Manipulatives, will help teachers and students validate the Pythagorean Theorem both geometrically and algebraically. It can be used interactively with the Smartboard and the Promethean Board to create a better understanding of the topic.
Pythagorean Theorem Manipulatives
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Assessment Questions
Assessment Questions
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FSA Sample Question
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FSA Sample Question
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Videos of Expert Instruction
Videos of Expert Instruction
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This resource gives an animated and then annotated proof of the Pythagorean Theorem.
Annotated Proof of the Pythagorean Theorem
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Use Real Link and Title
Math Literature
Math Literature
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It is a great litmus test to measure whether students’ can successfully explain the proof.
How Can We Correct The Scarecrow?
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Joining Two Midpoints of Sides of a Triangle
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The purpose of this task is to prove the Pythagorean theorem using similar triangles.
Pythagorean Theorem