yes
If a tile is a square or rectangle, cut the tile from corner to corner and you will create two triangles.
Yes a triangle will tessellate leaving no gaps or overlaps
Yes.
Yes.
A Triangle with a perfectly 90 Degree angle, which also should have a corner which is perfectly square. :D
yes it does
No.
No
heptagon and an equilateral triangle
An [equilateral] triangle, square and hexagon are the only regular polygons which, by themselves, will tile a surface.
Yes.