triangles

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Across
  1. 2. circle whose center is the intersection of two of definition*
  2. 5. the symmetry axis of an angle
  3. 8. connects the midpoint of a side and the opposite vertex
  4. 9. perpendicular to one side and through the opposite side
  5. 11. 3 in a triangle
Down
  1. 1. circle whose center is the intersection of two of the definition #
  2. 3. Pythagoras' favourite!
  3. 4. the symmetry axis of a side
  4. 5. their sum is always 180°
  5. 6. all its angles measure 60°
  6. 7. intersection of two of definition %
  7. 10. a triangle with only one symmetry axis