The parallel sides of the trapezoid [[$ ABCD $]] are [[$ AB = 8 $]] and [[$ DC = 6 $]]. The other side of the trapezoid is [[$ DA = 5 $]]. How long is the side [[$ BC $]], when the area of the trapezoid is [[$ 28 $]]? (Note two possibilities.) (Source: Finnish matriculation exam, autumn 1994)

Take a picture of your solution and return it to the submission folder.

Answer: The side is either or .