Answers

2014-07-13T22:16:40+08:00
A=s²
s²+240= (s+12) (s+12)
s²+240=s²+24s+144
s²=s²+24s+144-240
s²=s²+24s-96
24s-96=0
24s=96
s=4
the original lenght of the square 4. 
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