A postcard is in the shape of a parallelogram. A parallelogram is a quadrilateral with two pair of parallel sides, opposite sides and opposite angles are equal.
Since, the postcard has an area of 12 square inches.
Since, area of parallelogram =
As area of parallelogram is 12, it means that the product of base and height is 12 square inches.
So, the possible dimensions of postcard are 3 inches and 4 inches and 2 inches and 6 inches.
So, base = 3 inches , height = 4 inches or base = 4 inches , height = 3 inches.
So, base = 2 inches, height = 6 inches or base = 6 inches , height = 2 inches.