(1) can be solved directly by Pythagorean theorem;

(2) firstly, taking AC, BC and AB as sides, making square A, square BCNM and square ABHF；; ; And get the answer.

Answer:

Solution: (1) AC 2+BC 2 = (√ 2) 2+32 =11;

So the answer is:11;

(2) Aced Square, BCNM Square and ABHF Square; Take AC, BC and AB as one side respectively;

Extend the intersection MN of DE at Q point, connect QC, and translate QC to AG and BP positions. The straight line GP intersects AF and BH at T point and S point respectively.

Then the quadrilateral ABST is the demand.