Wpf \ MVVM - Where should I put view related properties?

I'm building a WPF application, using MVVM pattern. Let's I have two bars (rectangles) that should change their length according to the ratio between two numbers. For example, if I decide of total length of 100, and one number is 2 and the other is 3, I would like the first bar to be of length 40, and the second one of length 60.

I have these numbers saved as properties in my ViewModel, but my question is what should the bars width attribute be bound to. I could just add two more properties to the ViewModel one for each bar width, but it doesn't feel right, because this is specific for the view.

Any suggestions?

Thanks,

Gal