Answer:
shorter piece = 6. longer piece = 12
Step-by-step explanation:
short piece = s
long piece = l
l+s= 18
l= 6+s , substitute
6+s+s = 18
6+2s= 18
2s= 18-6
2s= 12
s=12/2
s= 6= shorter piece
l= 6+s
l= 6+6= 12 = longer piece
18.9
361-4 = 357
the root of 357 is 18.9 when rounded