Answer:
7. parallelogram
8. square
9. trapezoid (trapezium) (maybe "acute" - can't see the whole image)
10. rhombus
11. ?
12. rectangle
13. equilateral triangle
14. scalene triangle
15, 16, 17 and 18 are all isosceles triangles as they have 2 sides of equal length
I would say the object will float because the density of water is 999.99kg/m which is slightly less than 1g but still more than the object.
