Step-by-step explanation:
we do know that the area of a rectangle is length × width.
we know the total area and the width of the rug, so
12 = length × 3
length = 12/3 = 4 meters.
the perimeter of a rectangle is the whole way around it : 2 times the length and 2 times the width.
perimeter = 2×4 + 2×3 = 8 + 6 = 14 meters