Since each of the cards has two distinct dimensions and the cards cannot​ overlap, there are only 2 possible ways to arrange them into a larger polygon.
Part 2
The cards can be connected by the sides that are 7 in. ​long, or they can be connected by the sides that are 9 in. long.
Part 3
To obtain the perimeter of the polygon obtained by joining the cards along their longer side of 7 in.​, count the number of shorter sides that are on the outside edge of the polygon. Then count the number of longer sides that are on the outside edge of the polygon.