Is a rectangle, a square, or a triangle considered "plane"?

Question

Planes are usually illustrated as four-sided figures. A rectangle and a square are both four-sided figures; however, planes are usually drawn parallelograms. How about the triangle? Is it considered as a plane?

Answer 1

None of those are "planes".

A plane is drawn as a square simply because of the limitations of a sheet of paper.

A plane is infinite in two directions. It has no start or end point on the xy axis. A sheet of paper of course does have start end end points. Usually 8x11

None of rectangels, squares, or triangles are planes. They are all subsets of them. And darned small ones at that.

-Dio

Answer 2

A rectangle, a square or a triangle are planar shapes. They are represented in only 2 dimensions. They are NOT solid figures.
The idea od plane: Plane (straight plane) is 2 dimensioal extended enlessly. No start and no beginning to a plane. We generally represent plains on paper as a rectangle or a square. This does not mean that the plane has those boundaries. Plane (straight plane) has no such boundaries.
A rectangle lies on a plane. A triangle lies on a plane.

Answer 3

Planes are infinite in the 2 dimensions, they are just drawn as parallelograms in order to visualise a plane. Neither rectangles, squares nor triangles are planes ... they are a part of it.

Answer 4

Planes are infinite in the 2 dimensions, they are just drawn as parallelograms in order to visualise a plane. Neither rectangles, squares nor triangles are planes ... they are a part of it.

Answer 5

It is still a plane. I think a plane is a two dimensional shape. You can define any triangle, rectangle, circle ellipse using only two dimensions, x and y.

WL

Answer 6

yes, and a cube or sphere and stuff are not

Answer 7

i think so.