Mathematics

Problem

A circular sector has a perimeter of

40\,\text{cm}

, which includes the lengths of its two radii and its arc. If the central angle of the sector is

1.2\,\text{rad}

, find the radius of the sector (nearest tenth of a centimetre). a)

19.8\,\text{cm}

6.9\,\text{cm}

12.5\,\text{cm}

16.7\,\text{cm}