LB = 343,000
B = 343,000 / L
minimizing perimeter is same as minimizing semi-perimeter S
S = L + B = L + 343,000 / L
S' = 1 - 343,000 /L^2
setting S' to zero & taking the +ve value,
L = sqrt(343,000) = 585.66 m
since a rectangle with integer sides is wanted,
dimensions = 585 m x 586 m
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