Solution
For this case we know this_
P1= 18mm
And the perimeter is given by:
18mm = 2*2mm + 2*H
18-4 = 2H
H= 7mm
The scale factor is:
6mm/2mm = 3
Then the height for the second rectangle is:
7*3 = 21mm
Therefore the perimeter is
P2= 2*6mm + 2* 21mm = 12+ 42 mm= 54mm