If I have two images (logos) in two separate svg files, and I would like to combine them into a third svg file containing both logos, how should I do that?

I can open the two svg files in karbon, select a shape in one, paste it to the other, and save as a new file.
I was able to see both shapes in Karbon, but not in other applications, such as kolourpaint or chromium, until I changed the page size to include both shapes.

Now the problem is that the shapes are small relative to the page size.
Can I either shrink the page to just include the shapes?
Or can I expand the shapes maintaining their relative dimensions?

The trick is to hold shift while re-sizing the shapes.