interer of a polygon smallest angle is 120 degree and common dif is 5 degreen find no of sids

• sum of the interior angles of polygon=(n − 2)*180 degrees
  given a=120,cd=5(i.e angles are in AP)
  so S=n/2[2a+(n-1)*d]
  or (n-2)*180=n/2[2*120+(n-1)*5]
  or (n-2)*72=n[48+n-1]
  or 72n-144=n^2+47n
  or n^2-25n+144=0
  or (n-16)(n-9)=0
  or n=16 or 9
• 11 years agoHelpfull: Yes(4) No(0)
• sum of the interior angles of polygon=(n − 2)*180 degrees
  given a=120,cd=5(i.e angles are in AP)
  so S=n/2[a+(n-1)*d]
  or (n-2)*180=n/2[120+(n-1)*5]
  180-360/n degrees
  or (n-2)*72=n[24+n-1]
  or 72n-144=n^2+23n
  or n^2-49n+144=0
  
• 11 years agoHelpfull: Yes(0) No(0)
• 180(n-2) = n/2( 120 + 120 + 5(n-1))
  If you simplify, you get
  5n^2 -125n +720 =0
  n^2 -25n +144 =0
  (n -16)(n-9) =0
  n =16 or n =9
• 11 years agoHelpfull: Yes(0) No(0)