Adjust dimension to keep constant area

Hello,

I have a very simple request, but I can't  figure it out on my own. I'm attaching a sketch. In it, there are 3 solid lines, forming a triangle. Two of them are defined, but the last one is not - it lacks height dimension. I want to dimension it by equation so that the resulting area of the triangle (formed by solid lines) would be 2 square centimeters. How do I do that?

This is a simple example, but I'm working with complex shapes including splines, circles, and so on, where the same is required - to adjust one line to keep the area equal to desired number. So a simple trigonometry might work with triangle, but won't work with complex shapes.

Can anyone help, please?

SolidworksSketching