length = 126 yards and width = 44 yards
let the width = w then length = 3w - 6
perimeter = 2( length + width)
= 2( 3w - 6 + w) = 2( 4w - 6) = 8w - 12
noe perimeter = 340 hence
8w - 12 = 340
add 12 to both sides
8w = 340 + 12 = 352
divide both sides by 8 ⇒ w = = 44
thus width = 44 yards and length = ( 3 × 44) - 6 = 126 yards