perimeter = $14$ meters
Work Step by Step
RECALL: (1) The perimeter of a polygon is equal to the sum of the lengths of all its sides. (2) A square has four equal sides. This means that the three unknown side lengths of the square are all $3.5$ meters. Add the lengths of all the sides to find the perimeter: perimeter = $3.5+3.5+3.5+3.5= 14$ meters.