Grade 8 · Geometry
The Pythagorean Theorem
The Pythagorean theorem is ancient and indispensable. Students discover that in a right triangle, the squares on the two legs add to the square on the hypotenuse — and learn to apply it in both directions (finding a missing side; checking whether a triangle is right-angled). Distance problems on coordinate grids give the theorem immediate geometric meaning.
LESSON VIDEO
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Lesson video
A short walkthrough to play in class or assign for flipped/at-home viewing.
WHAT STUDENTS WILL LEARN
✓State and apply the Pythagorean theorem: a² + b² = c²
✓Determine whether a triangle is a right triangle using the converse
✓Find missing side lengths in right triangles
✓Apply the theorem to real-world distance and measurement problems