Illustrative Mathematics
Two Wheels and a Belt
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
Illustrative Mathematics
Seven Circles III
A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...
Curated OER
The Random Walk II
Deep mathematical thinking is found with just a coin and a number line. Combining computing some probabilities in a discrete situation, and the interpretation of a function, this simple task gives learners a lot to think about on...
101 Questions
Falling Rocks
Can you determine how far down a rock drops without visual clues? Viewers observe a clip from a movie testing vertical distance only based on sound. They must determine if it is safe to drop down themselves or if it is farther than their...
PBL Pathways
Arch Project
Model real-life structures with mathematics. A project-based lesson presents a problem situation requiring classes to develop a function to model the St. Louis Arch and the Rainbow Bridge in Arizona. They create their models by...