How many diagonals can be drawn by joining the angular points of an octagon?
2013
How many diagonals can be drawn by joining the angular points of an octagon?
- A.
14
- B.
20
- C.
21
- D.
28
Attempted by 49 students.
Show answer & explanation
Correct answer: B
The number of diagonals in an n-sided polygon is calculated using the formula n(n-3)/2. For an octagon, n = 8. Substituting this value: 8(8-3)/2 = 8(5)/2 = 40/2 = 20. Therefore, there are 20 diagonals.