Super activity from the original Standards Unit Improving Learning in Mathematics but now supplied with ActivInspire and PowerPoint files, an interactive Excel file (used to generate the tables and show partial information) plus the original Teacher Notes in pdf form together with some additional examples). Area of triangles is an important feature of this work. For 50 more like this from the Standards Unit see here.

ActivInspire Flipchart (includes all other files except PowerPoint)
Excel fileTeacher Notes (pdf)
Additional 6 questions (pdf)