Geometry Test Puzzle

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Across
  1. 1. A flat surface that extends infinitely in all directions (5 letters).
  2. 4. Points that lie on the same straight line (9 letters).
Down
  1. 1. A specific location in space represented by a dot (4 letters).
  2. 2. a two-dimensional figure formed by three or more points that are not collinear (3 letters).
  3. 3. A straight path that extends infinitely in both directions (4 letters).
  4. 5. A part of a line that has one endpoint and extends infinitely in one direction (3 letters).