word chain

12345678910111213141516
Across
  1. 3. Two lines don't have the intersection point
  2. 4. Parallelogram with all sides of equal length
  3. 7. The two lines intersect at 90 °
  4. 8. Space taken up by a 3D object
  5. 10. The Angle is less than 90 degrees
  6. 13. 7-2=5 in this case 7
  7. 14. To discover,to get
  8. 15. The bottom edge side of a graph
  9. 16. To prove,to explain,to guide
Down
  1. 1. To calculate or to judge the value
  2. 2. Space covered inside a circle
  3. 5. Every decimal have got
  4. 6. How many number in a number
  5. 9. A lot of points
  6. 11. Have three angles
  7. 12. Middle number