Yes
A regular hexagon will tessellate.
Yes because it will tessellate
yes it will
If their interior angles are a factor of 360 degrees, they will tessellate. Otherwise, they can't.
A regular octagon will not tessellate but an irregular one can.
Yes a triangle will tessellate leaving no gaps or overlaps
Sort of. Triangle is one of the shape that may tessellate(fit tightly). But one may argue that triangle is not a square (for sure), nor a tile (yet I think it may be) to a tessellate.
The rectangle is the simplest and most obvious case of a geometrical form that can tile a plane.
If it's interior angle is a factor of 360 then it will tessellate such as a square, a regular hexagon and an equilateral triangle.
For a shape to tile a plane, it must be capable of sharing a border with a copy of itself. Circles cannot do this; two circles which do not overlap touch in at most one point.
Find the area of the tile and this will depend on the shape of the tile. Tiles for regular or semi-regular tessellation may be triangular, quadrilateral (square, rectangular, rhombic, parallelograms, trapeziums), hexagonal or octagonal. The formula for the area in each case, is likely to be different.
I would think that the obvious answer would be yes. maybe I am missing something in the question why would one think that you could not tile a seven sided polygon? * * * * * Yes, maybe you are missing something - mathematic reality. There are no polygons - regualr or irregular of 7 or more sides which will tessellate with identical shapes.