Geometry crossword puzzle

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Across
  1. 2. an angle less than 90 degrees but greater than 0 degrees
  2. 6. the amount of space within the perimeter of a 2D shape
  3. 8. curve with no endpoints and which completely encloses an area.
  4. 10. a quadrilateral with all equal sides
  5. 11. one of the lines of light that appear to radiate from a bright object
  6. 12. the perimeter of a circle
  7. 14. two line segments which cross to form 90 degree angles
  8. 16. Two figures that are congruent
  9. 19. exceeding 90 degrees but less than 180 degrees.
Down
  1. 1. A=2(1+2)a2
  2. 3. a 90 degree angle
  3. 4. D=2r
  4. 5. a figure having two parallel & non-parallel sides.
  5. 7. P = (L + W) × 2
  6. 9. a triangle in which all three sides have the same length
  7. 13. a straight line segment whose endpoints both lie on a circular arc
  8. 14. V=lwh/3
  9. 15. the intersection point of two sides of a plane
  10. 17. A location
  11. 18. a term used to describe what a 3D shape would like like if it was opened out and laid flat