The shape below is constructed using four semi-circles. It is called a Salinon.

What is the relationship between the area of the shaded region and the area of the circle whose diameter is $AB$?

Networks/Graph Theory. Creating and manipulating expressions and formulae. Area - circles, sectors and segments. Regular polygons and circles. 2D shapes and their properties. Generalising. Mathematical reasoning & proof. Inequalities. Polynomial functions and their roots. Circle properties and circle theorems.