Relating Triangles to Quadrilaterals

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Across
  1. 2. - a polygon with 4 sides and 3 angles
  2. 3. - it has pairs of opposite sides
  3. 4. segment - a line formed by connecting two consecutive vertices
  4. 5. - a polygon with 3 sides and 3 angles
Down
  1. 1. sides - two lines that meet a common endpoint
  2. 3. - closed plane figure made up of several line segments that are joined together