若3a=4b=5c
則1/a : 2/b : 3/c =??????
請例式!!我諗唔到點做...thx
比例的數!!!>
2009-02-25 9:11 pm
回答 (3)
2009-02-25 10:54 pm
✔ 最佳答案
若3a=4b=5c 則1/a : 2/b : 3/c =?????? 再加一條件 abc<>03,4,5 的最小公倍數 60
令 3a=4b=5c=60k
a=20k,b=15k,c=12k
b/2=7.5k,c/3=4k
a:b/2:c/3=20k:7.5k:4k=20:7.5:4
1/a:2/b:3/c=(1/20):(1/7.5):(1/4)
20*7.5*4=600
1/a:2/b:3/c=30:80:150=3:8:15
2009-02-25 11:26 pm
Let 3a = 4b = 5c = k
so 1/a = 3/k
1/b = 4/k and 2/b = 8/k
1/c = 5/k and 3/c = 15/k
so 1/a : 2/b : 3/c = 3/k : 8/k : 15/k = 3 : 8 : 15.
so 1/a = 3/k
1/b = 4/k and 2/b = 8/k
1/c = 5/k and 3/c = 15/k
so 1/a : 2/b : 3/c = 3/k : 8/k : 15/k = 3 : 8 : 15.
2009-02-25 9:51 pm
設 3a=4b=5c=k, 則1/a : 2/b : 3/c = ３：２ｘ４：３ｘ５＝３：８：１５
如果唔明白
3a=4b=5c，
３ａ＝４ｂ， ａ：ｂ＝４：３＝ ２０：１５
４ｂ＝５ｃ， ｂ：ｃ＝５：４＝ １５：１２
ａ：ｂ：ｃ＝２０：１５：１２
１／ａ：２／ｂ：３／ｃ＝ １／２０：２／１５：３／１２
＝３：８：１５
如果唔明白
3a=4b=5c，
３ａ＝４ｂ， ａ：ｂ＝４：３＝ ２０：１５
４ｂ＝５ｃ， ｂ：ｃ＝５：４＝ １５：１２
ａ：ｂ：ｃ＝２０：１５：１２
１／ａ：２／ｂ：３／ｃ＝ １／２０：２／１５：３／１２
＝３：８：１５
參考: myself
收錄日期: 2021-04-25 22:36:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090225000051KK00562