a. The gym has the shape of a rectangle.
The area of a rectangle is calculated as follows:

The base of the gym is x and its height is 15, then its area is:

b. The cafeteria is a rectangle with a height of 15 and a base of (x+3), then its area is:

c. The total area is the addition of the gym area and the cafeteria area.

d. The perimeter of a rectangle is calculated as follows:

Considering both the gym and the cafeteria, the base is x + x + 3 = 2x + 3 units long. The height is 15, then:
