Fill Me In!

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Across
  1. 2. angles having equal measure
  2. 4. figure formed by two rays meeting at a common endpoint.
  3. 6. cover of a book
  4. 7. to measure
  5. 9. earth
Down
  1. 1. ruler
  2. 3. a property of equality which a number is equal to itself
  3. 5. building blocks of geometry
  4. 6. figure with no length and width or simply with no dimension.
  5. 8. part of a line.