W=L/2+4
W=(L+8)/2
A=LW, using W from above we get:
A=L(L+8)/2
A=(L^2+8L)/2, and we are told that A=234 so
(L^2+8L)/2=234
L^2+8L=468
L^2+8L-468=0
L^2+26L-18L-468=0
L(L+26)-18(L+26)=0
(L-18)(L+26)=0, since L>0
L=18, and since W=(L+8)/2
W=13
So the length is 18 meters and the width is 13 meters.