Step 1 :Let w = width and l = length.
Step 2 :Perimeter formula: P = 2(w + l), Given values: P = 360, l = w + 60.
Step 3 :Substitute given values into perimeter formula and solve for w: 2(w + (w + 60)) = 360.
Step 4 :2(2w + 60) = 360.
Step 5 :4w + 120 = 360.
Step 6 :4w = 240.
Step 7 :w = 60.
Step 8 :Plug w into length equation to find l: l = w + 60 = 60 + 60 = 120.