Q. 35.0( 2 Votes )
Write the number of diagonals of an n-sided polygon.
Answer :
An n-sided polygon has n vertices.
By joining any two vertices of the polygon, we obtain either a side or a diagonal of the polygon.
Number of line segments obtained by joining the vertices of an n-sided polygon if we take two vertices at a time, number of
Ways of selection 2 out of n = nC2
Out of these lines, n lines are sides of the polygon.
Number of diagonals of the polygon =
nC2 – n – n
Rate this question :






















Prove that the product of 2n consecutive negative integers is divisible by (2n)!
RD Sharma - MathematicsThere are 10 lamps in a hall. Each one of them can be switched on independently. Find the number of ways in which the hall can be illuminated.[Hint: Required number = 210 – 1].
Mathematics - ExemplarIf n+1Cr+1 : nCr = 11 : 6 and nCr : n–1Cr–1 = 6 : 3, find n and r.
RS Aggarwal - MathematicsIf nCr–1 = 36, nCr = 84 and nCr+1 = 126, find r.
RS Aggarwal - MathematicsFill in the Blanks
If nPr = 840, nCr = 35, then r = ______.
Mathematics - ExemplarThe number of ways in which a team of eleven players can be selected from 22 players always including 2 of them and excluding 4 of them is
Mathematics - ExemplarTotal number of words formed by 2 vowels and 3 consonants taken from 4 vowels and 5 consonants is equal to
Mathematics - Exemplar