Geometry Puzzle

1234567891011121314151617
Across
  1. 3. example a special case for a proposed general principle and regularly shows up as an illustration
  2. 4. lines straight lines that never meet
  3. 9. formula
  4. 11. where the three medians of the triangle meet
  5. 12. 5 letter word starting with a and end with e
  6. 13. C= 2(pi)(r)
  7. 16. bisector line that proportionally splits the triangle into two segments
  8. 17. an explanation that is acknowledged without evidence
Down
  1. 1. angle this angle measures lower than 90°
  2. 2. L•W=
  3. 5. two adjacent angles that make a line
  4. 6. has 4 straights sides and the opposite sides are parallel
  5. 7. a shape that has 10 sides
  6. 8. ABC ≈ A’B’C’
  7. 10. triangle means two legs
  8. 14. the middle of a line segment
  9. 15. Quadrilateral with four equal sides