To form a trapezium using a single cut, the line drawn must be parallel to the base. Let’s assume that the line divides the sides in the ratio 'K : 1 - K'. Then the sides of the trapezium are 40(1 - K), 40, 40(1 -K ) and 40K. When two such trapeziums are placed beside each other such that one side is common we get a parallelogram whose sides are 40(1 - K ), 40 + 40K, 40(1 - K) and 40 + 40K. So the perimeter = 4 × 40 = 160 cm.