[問題]天山7-18

[lpwpete]

[問題]天山7-18
A rectangular region has a fence along three sides and a wall along the fourth side. The fenced side opposite the wall is twice the length of each of the other two fenced sides. If the area of the rectangular region is 128 square feet, what is the total length of the fence, in feet?
A. 4
B. 8
C. 16
D. 32
E. 64
Ans: D (句意不太懂!)

[aerobert]

一長方形區域有三面圍了籬笆，另一面是牆
牆對面的籬笆長度是牆兩邊籬笆長度的兩倍
如果這長方形區域的面積是128平方尺，問籬笆的總長是多少
設籬笆的短邊為a長邊就是2a，面積128=2a^2，所以可得a^2=64，a=8
籬笆長度為4a=32

[lpwpete]

真是好人!
感謝大大的詳解!