Let's first focus at the small pentagon:
It's total perimeter is 10 cm.
One of its side is given and it is 2 cm.
Perimeter/Side = 10 cm/2 cm = 5 sides
Therefore, we can also say that all sides of the pentagon is equal.
Since the two figures are said to be similar, we can also say that all sides of the large pentagon are also equal.
The perimeter is the sum of all sides length of a given figure.
Therefore, the perimeter of the large pentagon will be:
Perimeter = 5s
Where,
s = measure of its side.
We get,
Perimeter = 5s = 5(7) = 35 cm.
Therefore, the perimeter is 35 cm.