Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this lesson.
Curated OER
What Is Hyperbolic Geometry?
Ninth graders discuss the concept of hyperbolic geometry. They complete Internet geometry activities and write essays comparing and contrasting hyperbolic geometry to Euclidean geometry.