Quadrilaterals, triangles and circles

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Across
  1. 1. a quadrilateral with exactly one pair of parallel sides
  2. 6. a quadrilateral that looks like a diamond and has four equal sides but not always right angles
  3. 7. a triangle with exactly two equal sides
  4. 11. the distance around a circle
  5. 12. A triangle with all sides and all angles equal
Down
  1. 2. the line segment that goes from the center of a circle to the edge
  2. 3. a quadrilateral with four equal sides and four right angles
  3. 4. a quadrilateral with opposite sides parallel and equal
  4. 5. a triangle with one angle greater than 90°
  5. 8. a part of a circle shaped like a pizza slice
  6. 9. a triangle where all sides are different lengths
  7. 10. A straight line passing through the center of a circle and touching both sides