Solution: (1) As shown in the figure, A'B'C'D' is the figure to be made;

(2) According to Pythagorean theorem, OC= 12+22=5,

Is the path length of point C 90 when rotating? π? 5 180=52π;

(3) As can be seen from the figure, tan ∠ dab ′ = b ′ dab ′ = 42 = 2.