which polygon has no. of sides = diagonal (Eg. Pentagon

• nC2 - n = n
  n(n-1)/2 = 2n
  n^2 - 5n = 0
  
  n = 0 or 5
• 11 years agoHelpfull: Yes(7) No(1)
• Circle is of infinite side and diagonal
• 11 years agoHelpfull: Yes(3) No(3)
• number of diagonals of a polygon having sides n is given by the formula,
  number of diagonal=nC2-n
  but we have given that number of sides are same as number of diagonals.
  n=nC2-n
  2n=n(n-1)/2
  4n=n^2-n
  0=n^2-5n
  n-5=0
  n=5
  the polygon having 5 sides is pentagon.
• 11 years agoHelpfull: Yes(3) No(0)
• Pentagon with 5 sides and 5 diagonals.
• 11 years agoHelpfull: Yes(2) No(0)
• Pentagon has 5 sides and 5 diagonals.
  
  
• 11 years agoHelpfull: Yes(2) No(0)
• 0 , 5
  dont required any explanation
• 11 years agoHelpfull: Yes(0) No(0)
• Number of diagonal in any polynomial=nC2-n
  so if we take n=5,then 5C2-5 gives number of diagonal=5
  Hence pentagon is the answer
• 10 years agoHelpfull: Yes(0) No(0)
• Pentagon
  5 sides & 5 diagonals
• 10 years agoHelpfull: Yes(0) No(0)
• n=6
  
  Let us have a polygon of n sides . To form a diagonal , it needs 2 points not adjacent to each other . Thus , number of diagonals possible of a n-sided polygon = (n-2)c(2)
  
  Thus ,
  
  2n=(n-2)(n-3)
  n^2 - 7n + 6 = 0
  
  Thus n=6 (a polygon can't be of only one side ).
• 9 years agoHelpfull: Yes(0) No(0)
• n number of sides
• 9 years agoHelpfull: Yes(0) No(0)
• triangle triangle is having 3 sides and number of diagonal is also 3
• 8 years agoHelpfull: Yes(0) No(0)
• pentagon (nc2-n)
• 8 years agoHelpfull: Yes(0) No(0)