中3 math 百分法
回答 (4)
2007-08-27 8:55 am
✔ 最佳答案
設原來的長方形的長是x,闊是y新長方形面積
=x(1+18%)y(1-30%)
=0.826xy
長方形面積的變化百分比
=(0.826xy-xy)/xy*100%
= -17.4%
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其實x和y最後都會被約簡走,
所以可以簡單化為:
長方形面積的變化百分比
=[(1+18%)(1-30%)-1]*100%
= -17.4%
參考: me
2007-08-27 7:01 am
Let x and y be the length and width respectively.
Original area = xy
New length = 1.18x
New width = 0.7y
Hence, new area = 0.826xy
Thus, the 長方形面積的變化百分比 is 減少17.4%.
Original area = xy
New length = 1.18x
New width = 0.7y
Hence, new area = 0.826xy
Thus, the 長方形面積的變化百分比 is 減少17.4%.
參考: myself
2007-08-27 7:00 am
let original length is x, width is y
original area = xy
then, lenght increase 18% => 118%x
width decrease 30% => 70%y
the new area is now = 118% * 70% xy = 83% xy
so, the % of area change = 83% - 100% = -17%
original area = xy
then, lenght increase 18% => 118%x
width decrease 30% => 70%y
the new area is now = 118% * 70% xy = 83% xy
so, the % of area change = 83% - 100% = -17%
參考: myself
2007-08-27 6:59 am
設長方形長的原值是l, 闊的原值是w
長方形的原本面積=lw
長方形的新面積= l(1+18%) x w(1-30%)
=1.18l x 0.7w
=0.826lw
變化百分比 = (0.826lw-lw) / lw x 100%
=-17.4%
所以面積減少17.4%
長方形的原本面積=lw
長方形的新面積= l(1+18%) x w(1-30%)
=1.18l x 0.7w
=0.826lw
變化百分比 = (0.826lw-lw) / lw x 100%
=-17.4%
所以面積減少17.4%
參考: me
收錄日期: 2021-04-13 13:09:16
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070826000051KK04898