A quadrilateral is a four-sided shape. It could be a square, rectangle, kite, rhombus, parallelogram or trapezium. For any quadrilateral, the angles of the four corners add up to \(360^\circ\).

Read by Robert Blythe from the BBC Radio Drama Company. Once upon a time, a long time ago, there lived a perfect shape: Mr Square. He was the squarest of them all; he lived in a perfectly square ...