Answer
As per the statement: Mike has 2 mats that are in the shape of triangles.
It is also given that the scale factor of the two triangles mats is,
Each side of a image triangle is
times the length of the corresponding side of the pre image triangle.
Since, each side is scaled by a factor of 7/9.
Perimeter of a triangle defined as the sum of all the three sides of a triangle.
⇒ the sum of the three side side of a image triangle will also be scaled by a factor of 7/9 times the perimeter of a pre-image triangle.
Therefore, the ratio of the perimeters is,