for this, we can say they are similar and proportional to one another. If they are and the perimeter of the smaller figure is 7.3, we can find the perimeter of the larger figure by .....
7.3 ÷ 1.75 = 4.17..... then multiply this by the outside figure's side
4.17.... × 3.5 = 14.595 ... or 14.6
or
3.5 / 1.75 = gives us a dilation of 2.....so we can multiply 2 x 7.3 = 14.6