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Number of sides from the sum of the interior angles

Grade 8 math · Fieldbook Learning

Name ______________________ Date __________

Interior angle sum = (n − 2) × 180. Work backwards to find n.

  1. The interior angles of a polygon add up to 9720°. How many sides does the polygon have?
  2. The interior angles of a polygon add up to 2160°. How many sides does the polygon have?
  3. The interior angles of a polygon add up to 7560°. How many sides does the polygon have?
  4. The interior angles of a polygon add up to 10260°. How many sides does the polygon have?
  5. The interior angles of a polygon add up to 1980°. How many sides does the polygon have?
  6. The interior angles of a polygon add up to 6660°. How many sides does the polygon have?
  7. The interior angles of a polygon add up to 14040°. How many sides does the polygon have?
  8. The interior angles of a polygon add up to 3420°. How many sides does the polygon have?
  9. The interior angles of a polygon add up to 2340°. How many sides does the polygon have?
  10. The interior angles of a polygon add up to 3240°. How many sides does the polygon have?
  11. The interior angles of a polygon add up to 9900°. How many sides does the polygon have?
  12. The interior angles of a polygon add up to 3780°. How many sides does the polygon have?
  13. The interior angles of a polygon add up to 6120°. How many sides does the polygon have?
  14. The interior angles of a polygon add up to 7740°. How many sides does the polygon have?
  15. The interior angles of a polygon add up to 8640°. How many sides does the polygon have?
  16. The interior angles of a polygon add up to 15300°. How many sides does the polygon have?
  17. The interior angles of a polygon add up to 34920°. How many sides does the polygon have?
  18. The interior angles of a polygon add up to 19080°. How many sides does the polygon have?
  19. The interior angles of a polygon add up to 11160°. How many sides does the polygon have?
  20. The interior angles of a polygon add up to 21780°. How many sides does the polygon have?
More free practice: fieldbooklearning.com/ca/practice/grade-8/number-of-sides-from-the-sum-of-the-interior-angles/

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Answer key: Number of sides from the sum of the interior angles

  1. 56
  2. 14
  3. 44
  4. 59
  5. 13
  6. 39
  7. 80
  8. 21
  9. 15
  10. 20
  11. 57
  12. 23
  13. 36
  14. 45
  15. 50
  16. 87
  17. 196
  18. 108
  19. 64
  20. 123