For each piece we have that the area is:
 A = (b) * (h)
 Where,
 b: base of the parallelogram
 h: height of the parallelogram
 Substituting values:
 A = (4) * (2.5)
 A = 10 in ^ 2
 Then, for 85 pieces we have:
 (85) * (10) = 850 in ^ 2
 Answer:
 the total area of the border was:
 850 in ^ 2