The paper discusses technology that can help students master four triangle centers -- circumcenter, incenter, orthocenter, and centroid. The technologies are a collection of web-based apps and dynamic geometry software. Through use of these technologies, multiple examples can be considered, which can lead students to generalizations about triangle centers.
Triangle Center Technology
Using Scaffolding to Scale-up Justifications
Carolyn James, Ana Casas, and Douglas Grant
Encouraging students to justify earlier as they attempt to solve an open-ended task can lead to greater understanding and engagement.
Mathematical Explorations: A New Twist on Collaborative Learning
Stephanie M. Butman
Research on students' learning has made it clear that learning happens through an interaction with others and through communication. In the classroom, the more students talk and discuss their ideas, the more they learn. However, within a one-hour period, it is hard to give everyone an equal opportunity to talk and share their ideas. Organizing students in groups distributes classroom talk more widely and equitably (Cohen and Lotan 1997).
Mathematical Explorations: Find the Distance: No Formula Necessary
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.
If Only Clairaut Had Dynamic Geometry Tools
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.
Anne Roche and Doug M. Clarke
Students display a wide variety of creative mathematical thinking and misconceptions when they complete a classroom task that focuses on proportional reasoning.
Quick Reads: Sure, We Can Make Smaller Pieces
a good idea in a small package
Michael J. Gilbert
The topic of limit is explored by examining a circle's successively smaller sectors.
Bird Boxes Build Content Area Knowledge
Sherri Ann Cianca
Communicating reasoning and constructing models fold nicely into a geometry activity involving the building of nesting boxes.
Capturing Thinking on the Talk Frame
Tutita M. Casa
This instructional tool helps students engage in discussions that foster student reasoning, then settle on correct mathematics.
Using Tiered Explorations to Promote Reasoning
Cory A. Bennett
Address the needs of diverse learners with a class structure that is designed around a crime scene theme and based on student choice and perceptions of the math being studied.