How many diagonals does a decagon (a polygon with 10 sides) have?
Correct answer B. 35
Explanation
Diagonals = n(n - 3)/2 = 10 x 7/2 = 35. 10C2 = 45 counts the 10 sides as well.
Answer checked How we write and check questions
Tip: press A, B, C or D to answer, and N for the next question.
Advertisement
More Permutation and Combination questions
See allIn how many different ways can the letters of the word ‘BALLOON’ be arranged?
Correct answer B. 1260
In how many different ways can the letters of the word ‘SUCCESS’ be arranged?
Correct answer A. 420
Advertisement
In how many ways can the letters of the word ‘PENCIL’ be arranged so that the vowels always come together?
Correct answer D. 240
In how many different ways can the letters of the word ‘BANANA’ be arranged?
Correct answer B. 60
Discussion