CA Foundation P3 · Chapter 5 · Question 7 of 9
The number of diagonals of a polygon with 12 sides is:
Test yourself: pick an answer
Reveal answer & explanation
Correct answer: B) 54
Explanation
Lines joining any two vertices = ¹²C₂ = 66. Of these, 12 are sides. Diagonals = 66 − 12 = 54. Equivalently n(n − 3)/2 = 12 x 9 / 2 = 54.
More Basic Concepts of Permutations and Combinations MCQs
- Q9If ⁿC₈ = ⁿC₁₂, then ⁿC₁₇ is equal to:
- Q1The number of different arrangements of the letters of the word LEDGER is:
- Q2In how many ways can a committee of 3 be chosen from 8 persons?
- Q3A committee of 5 is to be formed from 6 men and 4 women. In how many ways can this be done if the committee must contain exactly 2 women?
- Q4In how many ways can 7 persons be seated around a circular table?