quiz ig?

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Across
  1. 3. are basis of maths
  2. 6. triangles have 3 equal sides
  3. 8. angle is 90 degrees
  4. 9. can have an infinite number of diameters bisecting it
Down
  1. 1. numbers have never ending and un-repeating decimal places
  2. 2. are add on's onto the numbers
  3. 4. is difficult
  4. 5. has 4 sides
  5. 7. is written as 22/7 as a way for its everyday use