Greatest distance between vertices of nested squares with perimeters 20 and 28

[Wildcat]

Homework Statement

A square of perimeter 20 is inscribed in a square of perimeter 28. What is the greatest distance between a vertex of the inner square and a vertex of the outer square.

Homework Equations

The Attempt at a Solution

I have a question. Can a square be inscribed in another square by having it sit along the base and the side of the bigger square? Does it only have to touch vertice to side?

 

[ehild]

See:http://en.wikipedia.org/wiki/Inscribed_figure

ehild

 

[Wildcat]

Thanks!