How can I make a chart like this on Excel (where I can control/define the size of the circles)?

There is a graph that should be called something like "bubbles". It uses 3 rows of data standard X and Y + Z that defines the size of the circles. It looks something like this. Altough it would be difficult to align them the same way as you show it on the picture.

You can do this with shapes and a macro to change the size of the red, green and orange circles in proportion to the blue circle.  The file at http://www.mediafire.com/view/2t1ipooa6o5lzov/CircleChart.xlsm has the chart, cells for inputting the values and the macro. It doesn't have any error checking and could be cleaned up some but it'll give you the idea.

Below is a completely unnecessary bubble chart implementation but gives you exactly what you want: https://www.dropbox.com/s/0alsjab2jxzqci5/circle_test.xlsx I spent some time on this because I was curious how bubble charts are automatically resized in Excel. For those of you who are interested: Bubble charts are normalized on the largest bubble, and the size of your graph. At 100% scaling, the diameter of the bubble takes up ~24% of the shorter axis (based on size of the graph). At 300% scaling, the bubble takes ~48.6% of the shorter axis. If you make a hamburger graph, and make the y axis length 1, you can figure out how overlay each of the circles so the bottoms touch. Therefore, you can change the sizes of the circles and make it all still look right. Once again, this hack was pretty damned unnecessary but oh well. The things we do.

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