Please wait...
1800-212-7858 (Toll Free)
9:00am - 8:00pm IST all days


Thanks, You will receive a call shortly.
Customer Support

You are very important to us

For any content/service related issues please contact on this toll free number


Mon to Sat - 11 AM to 8 PM

CBSE - IX - Mathematics

In a hundred sided polygon can you tell the number of diagonals

Asked by 23rd February 2009, 5:18 PM
Answered by Expert


For a n sided figure,

 if you join each point to every other point you will have total number of line segments as [n(-1)]/2]

( we are dividing by 2 because line segments get repeated while counting. e.g. if we are counting a line segment from a point say A to another point C, then the same line segment gets counted when counting the number of line segments from C)

But this number contains all the sides and all the diagonals.

So the number of diagonals =

= total number of line segments - the number of sides



For a quadrilateral, n=4

so number of diagonals=[4(4-1)/2]-4



for a pentagon,

 the number of diagonals =




you can verify this by drawing a figure.

This property can be generelised for n=100 and you will get the required answer.


Answered by Expert 23rd February 2009, 6:11 PM

Rate this answer

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10

You have rated this answer /10

Report an issue
Your answer has been posted successfully!

Related Question

Answered by Expert
Answered by Expert
Answered by Expert