Try

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Across
  1. 3. the name for an 8 sided polygon
  2. 5. an angle that measures greater than 90 degrees
  3. 6. a math sentence made up of numbers and symbols but no equal sign
  4. 9. positive and negative whole numbers
  5. 10. cut the circle in half
Down
  1. 1. the number being multiplied by the variable
  2. 2. When comparing a number out of 100
  3. 4. the exact same shape and size
  4. 7. the irrational number which is the ratio of the circumference to the diameter of a circle
  5. 8. the acronym used to remember the order of operations
  6. 11. is half the size of a diameter