Geoboard
Click pegs to stretch a band round them. Close the shape by clicking the first peg again. Area and perimeter come up for each shape.
How to use it
- Click pegs in order. When you have three or more, click the first peg again to close the band.
- Area is in squares (the gap between pegs is one unit) and perimeter in units, so a 2 by 3 rectangle gives area 6, perimeter 10. Untick "Area and perimeter" to hide the answers while the class works them out.
- Change the colour for a second shape. Undo takes off the last peg or the last shape.