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...
Unit Plan
Mathematics Vision Project

Circles: A Geometric Perspective

For Teachers 10th - 12th Standards
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Lesson Plan
Alabama Learning Exchange

It's Around There Somewhere! Perimeter, and Circumference

For Teachers 6th - 8th Standards
Explore the concept of building equations for perimeter and circumference. Learners use rulers to measure the perimeter of half a sheet of paper.  Then fold the sheet of paper numerous times, each time measuring perimeter. ...