Arc Lengths

An arc is part of the circumference, and the angle at the centre tells you what fraction of the circle it is. In NSW Year 8 maths (NESA outcome MA4‑LEN‑C‑01) the arc length is \(l = \frac{\theta}{360} \times 2\pi r\), given exactly in terms of \(\pi\) or rounded.

You will find minor and major arcs, including ones with a reflex angle at the centre, use \(\pi = \frac{22}{7}\) when a question says to, and work backwards to the angle or the radius. You will also find how far the tip of a clock's minute hand travels, the radius of a bend in a bike path, the swing of a pendulum and the distance between two towns on the equator. It is part of Year 8 Area and Perimeter.