F5Math P&C
回答 (2)
2012-04-12 5:10 pm
✔ 最佳答案
No. of diagonal of a n-sided polygon is C(n,2)-n2012-04-12 09:13:33 補充：
Therefore,
C(n,2)-n=252
==> n^2-3n-504=0
==> (n-24)(n+21)=0
==> n=24
Ans : no. of sides is 24
2012-04-12 5:09 pm
252diagonals=504points=504sides
2012-04-12 09:13:18 補充：
誤會左對角線 應該係
(n^2-3n)/2=252
n^2-3n=504
n^2-3n-504=0
(n-24)(n+21)=0
n=24 or -21
由於係number of sides 不會係負數
所以n=24
2012-04-12 09:13:18 補充：
誤會左對角線 應該係
(n^2-3n)/2=252
n^2-3n=504
n^2-3n-504=0
(n-24)(n+21)=0
n=24 or -21
由於係number of sides 不會係負數
所以n=24
收錄日期: 2021-04-13 18:37:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120412000051KK00141