Question

OAB is a major sector of the circle below.

Work out the length of the major arc AB in
terms of π.
B
6 cm
cm
120°
A
Not drawn accurately

Answer 1

`\textit{arc's length}\\\\ s = \cfrac{\theta \pi r}{180} ~~ \begin{cases} r=radius\\ \theta =\stackrel{degrees}{angle}\\[-0.5em] \hrulefill\\ r=6\\ \theta =240 \end{cases}\implies s=\cfrac{(240)\pi (6)}{180}\implies s=8\pi`