I want to draw a graph that is similar to below image in Illustrator. I can use the Rectangle tool to draw a graph that looks like it. However, I want to draw something proportionally (according to the size info in below image) so that it looks real (at least for size). How can I do that in Illustrator?
You can draw to exact proportions with the Rectangle Tool. Simply choose the Rectangle Tool and click on your artboard instead of click and drag. This will bring up a dialog box for you to define your rectangle proportions.
This dialog, like many others in Illustrator, will let you input any unit of measure no matter what your document measurement units are set for.
For example, my document measurement units in the picture below is set to points- I input 9 cm for width and 21 cm for height and it did the math for me and shows my measurements as points- because that is what this document is set to measure in.
You can change the document measurement units by going to Illustrator> Preferences> Units and change it to whatever your prefer to work in.