Answer:
The answer is 180°
Explanation:
For a hexagon to rotate unto itself, the shape after rotation and relative length and angles is identical to the original figures.
Since this hexagon is irregular i.e has sides of different lengths, and from the facts given, opposite sides and angles are equal.
This implies top/bottom, left/right and sides and angles 180° apart are identical.
Hence, only a 180° rotation will yield an identical hexagon.