Using technology to solve triangle construction problems, students apply their knowledge of points of concurrency, coordinate geometry, and transformational geometry.
Ryota Matsuura and Yu Yan Xu
This activity involves finding the distance between two points in a coordinate plane and emphasizes reasoning from repeated calculations, which is one of the mathematical practices specified by the Common Core State Standards for Mathematics.
Kevin C. Moore and Kevin R. LaForest
A connected introduction of angle measure and the sine function entails quantitative reasoning.
Agida G. Manizade and Marguerite M. Mason
When calculating the area of a trapezoid, students use a range of problem-solving strategies and measurement concepts.
Hyewon Chang and Barbara J. Reys
Using Clairaut's historic-dynamic approach and dynamic geometry tools in middle school can develop students' conceptual understanding before they encounter formal proof in geometry.
Harold B. Reiter, John Thornton, and G. Patrick Vennebush
Through KenKen puzzles, students can explore parity, counting, subsets, and various problem-solving strategies.
Jeffrey J. Wanko and Jennifer V. Nickell
Shapedoku puzzles combine logic and spatial reasoning with an understanding of basic geometric concepts.
Sherri Ann Cianca
Communicating reasoning and constructing models fold nicely into a geometry activity involving the building of nesting boxes.
Bobson Wong and Larisa Bukalov
Parallel geometry tasks with four levels of complexity involve students in writing and understanding proof.
Tutita M. Casa
This instructional tool helps students engage in discussions that foster student reasoning, then settle on correct mathematics.