Mathematical crossword

1234567891011
Across
  1. 3. What shape have all sides equal?
  2. 5. What does the letter t stand for?
  3. 7. An elongated square.
  4. 9. What does the letter v stand for?
Down
  1. 1. 3D triangle
  2. 2. Basic unit of length?
  3. 4. Basic unit of weight?
  4. 6. The math symbol opposite to minus?
  5. 8. 3D square?
  6. 10. What day is celebrated on the fourteenth of March?
  7. 11. What prime number after 7?