更新1:
Answer are 8cm, 24cm
F.4 Maths
2013-09-29 8:28 pm
A piece of 32 cm lng wire is cut into two different parts. Each part is bent to form a square as shown in the figure. If the total area enclosed by by two squares is 40cm^2, find the lengths of two parts of the wire.
回答 (1)
2013-09-29 8:49 pm
✔ 最佳答案
X + Y = 32(a)(X/4)^2 + (Y/4)^2 = 40(b)
from (a)
Y = 32-X put into (b)
(X/4)^2 + [(32-X)/4]^2 = 40
Solve it.
2013-09-29 12:56:58 補充：
rearrange gives : X^2 + (32-X)^2 = 640
X^2 + 1024 - 64X + X^2 = 640
2X^2 - 64X +384 = 0
X^2 - 32X + 192 = 0
use -b +- root(b^2 ........
Gives X = 24 or 4
2013-09-29 12:58:48 補充：
then X = 24 Y = 8
24/4 = 6
8/4 = 2
6^2 + 2^2 = 40
X = 4 Y = 28 does not fit and has to be rejected.
收錄日期: 2021-04-27 20:33:13
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130929000051KK00079