Go here for a non-embeded dynamic worksheet.

This tool allows users to compare a ratios (wholes from 1 to 500, parts up to 2 times the whole) visually and change the wholes and parts using sliders. A proportion and decimal values are shown.

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com