Using technology to solve triangle construction problems, students apply their knowledge of points of concurrency, coordinate geometry, and transformational geometry.
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.
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.
Bobson Wong and Larisa Bukalov
Parallel geometry tasks with four levels of complexity involve students in writing and understanding proof.
Gloriana González and Anna F. DeJarnette
An open-ended problem about a circle illustrates how problem-based instruction can enable students to develop reasoning and sense-making skills.
Michael K. Weiss and Deborah Moore-Russo
The moves that mathematicians use to generate new questions can also be used by teachers and students to tie content together and spur exploration.
Anna E. Baccaglini-Frank
In this activity, students learn to make conjectures about properties that do not change.
Zhonghong Jiang and George E. O'Brien
Using technology to explore the Three Altitudes of a Triangle problem, students devise many proofs for their conjectures.