Curriculum/Euclid: The Elements/The Pythagorean Theorem
Euclid: The ElementsGrade 8dialectic Stage

The Pythagorean Theorem

Proposition XLVII proves the most famous theorem in mathematics: in a right triangle, the square on the hypotenuse equals the sum of the squares on the other two sides. Euclid's proof constructs squares on all three sides, then shows through a series of triangle congruences and area comparisons that the large square equals the sum of the two smaller squares.

The Text

What You'll Learn

1

Comprehension

States the theorem: square on hypotenuse = sum of squares on other sides

2

Cause & Consequence

Explains why the line CL is drawn parallel to AG

3

Meaning

Distinguishes between knowing the theorem empirically and proving it logically

4

Evidence

Points to a specific step in the proof

5

Defense

Maintains or thoughtfully revises their position under challenge

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  • 1.Read the text carefully
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