Answer:
I think it's 7- 2i over 3. hopefully that helps
I think it is the first and third one
2. Quadrilateral, rectangle, parallelogram
3. Quadrilateral, trapazoid
4. Quadrilateral
Most of the square numbers are even.so if we need to find root over we need an even number to convert it to perfect square.
See the example below






Some other triplets are
- (6,8,10)
- (5,12,13)
- (8,15,17)