If 5 squares of identical areas equal 45
then each square has an area of 45/5 = 9

since area of each square is 9; each side = 3

Now the main point is that the dotted square in the center does not count towards the perimeter because this part is hidden and we calculate the perimeter of only outer surface

so we have 4 squares. Each of these 4 squares have only 3 of 4 sides visible so we have perimeter of each square as 9 hence perimeter of 4 such square is 36
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This is my response to the question and may be incorrect. Feel free to rectify any mistakes