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 $AB$?

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