This lesson from Illuminations asks students to construct perpendicular bisectors, find circumcenters, calculate area, and use proportions to solve a real-world problem. Concepts taught in the lesson include...

"Informal notes" by Kevin Brown on geometry: constructing the heptadecagon, what mirrors do, the golden pentagon, the grazing goat and the lune, Napoleon's theorem, chess boards, Diophantine geodesic boxes, Zeno's mice...

This geometry lesson from Illuminations presents a real-world problem for students to solve with mathematical functions. The material involves constructing the circumcenter and incenter of a triangle. Learners will gain...

This geometry lesson from Illuminations involves using sidewalk chalk and rope to illustrate the locus definitions of ellipses and parabolas. Students will define conic sections, apply locus definitions and collaborate...

This geometry lesson from Illuminations introduces a hands-on learning activity for students in grades 9-12. The class will use pasta to create models of triangles. They will examine the relationship between sides and...