General instructions: At the bottom of the page you should see a screen with a rectangle, that can be moved. If you don't see this, you may need to use another browser (if you're using Explorer, try Firefox and vice versa), or you may need to update the Java on your computer. You can get it for free here: http://www.java.com/en/download/index.jsp
In the applet window below, there are several objects that you can move by clicking and dragging. Generally speaking, you can click and drag points, but not lines. I have tried to hide all of the dots that can't be dragged, so it should be that all of the (red) dots you can see, you can click on and drag to new positions.
If you want to measure something in the applet, you can drag the length measurement segment around next to it to check its length, or the angle measurement tool to check an angle, or you can drag the parallel lines over next to a pair of lines to check if they are parallel.
The rectangle: The rectangle you see is a rectangle-maker. This means that if you drag the points around in such a way that you still have a 4-sided figure (collapsing it to a line doesn't count!), the figure you have is an example of a rectangle.
To do: Find as many properties as you can that are always true for rectangles, and record them on your recording sheet.
Your choice: Some people like to measure things to check to make sure that what they think they see is correct. That's why I gave you the measurement tools that are on the right side of the applet. You don't have to use them if you are confident of your estimates.
Be sure to: drag around the rectangle maker to make lots of different shapes and sizes of rectangles. Make sure that your properties are true for all of the rectangles.
Rectangle