In order to derive the formula to calculate the angle at the centre of the sector, the formulae for the arc length and area of a sector can be rearranged so that we can calculate the fraction of ...

The circumference of a circle = \(\pi d\) or \(2\pi r\). Look at the sector of the circle shown below. To calculate the length of the arc, we need to know what fraction of the circle is shown. To do ...

I discuss a teaching experiment that sought to characterize precalculus students' angle measure understandings. The study's findings indicate that the students initially conceived angle measures in ...