100 inches
Let's use "x" to represent the length of a side of the smaller polygon, and let's use "y" to represent the corresponding length of a side of the larger polygon. We're told that the ratio of the side lengths is 3/5, so we can set up the equation:
y/x = 5/3
We're also told that the perimeter of the smaller polygon is 60 inches, so we can set up another equation using the fact that the smaller polygon has "n" sides:
nx = 60
Now, we want to find the perimeter of the larger polygon, which also has "n" sides. We can use the equation we set up earlier to write "y" in terms of "x":
y/x = 5/3
y = (5/3)x
Now we can substitute this expression for "y" into the formula for the perimeter of the larger polygon:
Perimeter of larger polygon = nx = n(5/3)x = (5/3)(nx) = (5/3)(60) = 100
So the perimeter of the larger polygon is 100 inches.