Perimeter of the rectangle?

Question

If the area of rectangle is 40, which of the following could be the perimeter of the rectangle? Indicate all such areas. A) 20, B) 40, C) 200, D)400, E)2000, F)4000 Answers are B,C,D,E,F

Answer 1

Area is equal to the product of the addends of one-half of the perimeter.

For A) 40 = x(10 - x) does a real solution exist?

Do the same for the other four choices.