We are given that each side of the Square Park measures 160 yards.
The Square Park has 4 sides.
The perimeter of the Square Park is given by
[tex]P=4s=4(160)=640\;yards[/tex]This means that if you walk around the outside of the Square Park one time then you would cover a distance of 640 yards.
It is given that Tina walked twice around the outside of the park.
[tex]2\times640=1280\;yards[/tex]Therefore, Tina walked 1280 yards.