Midpoints of the Sides of a Rectangle

Proposed Problem 3 What is the figure formed by joining the midpoints of the adjacent sides of a rectangle? Conjecture The figure formed by joinig the midpoints of the sides of a rectangle is a rhombus. Hint A rhombus is a quadrilateral with four equal sides.	Please enable Java for an interactive construction (with Cinderella).
	Drag free elements (free points A and B, or semi free point C) to alter the rectangle ABCD and observe the length of sides of the figure EFGH, which is formed by joining the midpoints of the adjacent sides of the rectangle ABCD to check the correctness of the made conjecture.