ABCD is a trapezium. Click and drag either of the blue points to change the shape of the trapezium.

Move the points B and C so that <A = <D.

- What observation can you make regarding the lengths of AB and DC?
- What is the special name given to the trapezium in question (1)?
- A trapezium is defined as a quadrilateral with at least one pair of parallel lines. By this defintion, trapeziums are inclusive of the parallelograms. Move the points B and C so that a parallelogram is formed. What properties tell you that this is a parallelogram?