National 5 Circle geometry Circle geometry Arc length is a fraction of circumference. Area of a sector is a fractions of the area of a circle. Both can be calculated using the angle at the centre ...

A more scientific explanation is that the Babylonians subdivided the circle using the angle on an equilateral triangle as the base unit — are we getting too technical for non-geometry students ...

Circle geometry Arc length is a fraction of circumference. Area of a sector is a fractions of the area of a circle. Both can be calculated using the angle at the centre and the diameter or radius.