CROSSWORD PUZZLE

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Across
  1. 3. A plane figure with four equal sides and four right angles.
  2. 6. A way of arranging identical plane shapes so that they completely cover an area without overlapping.
  3. 7. A figure whose sum of all the angles gives 180 degrees.
Down
  1. 1. A synonym of corner in mathematics.
  2. 2. In geometry, a figure of five sides and five angles.
  3. 4. The pentagon tiles are all ....
  4. 5. Who founded the 15th type of pentagonal tiling.