The perimeter of any quadrilateral is equal to the sum of the lengths of all four sides of this quadrilateral.
According to the condition of the problem, the lengths of the sides of this quadrilateral ABCD are: | AB | = | BC | = 15 mm, | CD | = 20 mm, | DA | = 25 mm, therefore, the perimeter P of this quadrilateral is:
P = | AB | + | BC | + | CD | + | DA | = 15 + 15 + 20 + 25 = 30 + 45 = 75 mm.
Answer: The perimeter of this quadrilateral is 75 mm.
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