Lucas's Crossword

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Across
  1. 2. a shape with four sides
  2. 6. 3.1415926535
  3. 7. A triangle with only 2 equal sides
Down
  1. 1. When an angle is at 90º
  2. 3. A shape with 10 straight sides and angles
  3. 4. A line that goes from the middle of a circle to the circumference
  4. 5. A triangle with no equal sides