Ellipses are not circles.
Because all circles are similar.
Small circles
No. There are big ones, medium ones, and little bitty ones.But all circles are similar.
small circles
Zero, or all if the circles coincide.
Yes
yes
a circle has 4 sides
Not all do. In fact, most do not.
Yes
Yes, all circles are similer, they all have 1 line, all the same shape, any quarter of a circle will always be 25%, but it the line is bigger they still have differances and similarities, e.g a circle can have a radius of 25cm while another can have a radius of 93984389569349billion miles