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What is the term for a set of points forming a flat surface extending in all directions?

  1. Line

  2. Plane

  3. Ray

  4. Point

The correct answer is: Plane

A plane is defined as a flat, two-dimensional surface that extends infinitely in all directions. It is characterized by having length and width, but no thickness. You can think of a plane like a sheet of paper that goes on forever in every direction, though you would never be able to see its infinite extent. In contrast, a line is a one-dimensional figure that extends infinitely in two directions, but does not have width or depth, so it does not fit the description of a flat surface. A ray is a part of a line that has a fixed starting point and extends infinitely in one direction, which also cannot be classified as a surface. A point, being a zero-dimensional entity, has no length, width, or depth, and thus cannot form a surface either. Therefore, the only term that accurately describes a flat surface extending in all directions is a plane.