College of Education

# Office for Mathematics, Science, and Technology Education

Resources Projects Contact
Home Pavel Java Geoboard

# The Online Geoboard

Instructional animation by Linda Stojanovska

## The Concept:

Use the Java Applet of a real Geoboard to construct any number of shapes without the limit of the actual Geoboard. The Geoboard gives the user a virtual rubber band which can then be stretched over the pegs in the board. Use the rubber band to construct shapes and study the relationship between the the shape of the rubber band and the area inside the rubber band.

## Instructions:

Drag any of the vertices of the polygon to change it's shape. Click the mouse near the border of the polygon and drag to create another vertex at that point. Double-click on a vertex to delete that vertex.

### Controls:

• Add: Click to insert a new rubber band of the current color.
• Remove: Click to remove the selected rubber band.
• Show/Hide Area: Click to show/hide the area and perimeter information.
• Show/Hide Sides: Click to show/hide the side lengths.
• Click the buttons along the bottom to change the current color. If a rubber band is selected, its color will change.

## The Purpose:

• Constructing shapes is much easier than on a real Geoboard and without the limit of the length of the rubber bands.
• Learn the relationship between the shape of the object and its area.
• Advanced: Determine how the area inside the rubber band can be easily calculated without having to measure anything.