Mathematical crossword

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Across
  1. 2. the Sum of its angles is 180
  2. 3. A triangle whose angles are equal
  3. 6. 4-sided polygon
  4. 7. A famous scientist who was interested in the right-angled triangle
Down
  1. 1. A natural number that can be negative
  2. 2. Type of transformation where we move objects
  3. 3. It must have an equal sign
  4. 4. It's an equation that has <, >, >=, or <=
  5. 5. You remember that once we say reflection
  6. 7. It's what you write to prove the RTP