Given:
- Radius of the sector, $ \displaystyle r = 7 $ cm
- Arc length, $ \displaystyle l = \frac{22}{3} $ cm
- We need to find the central angle $ \displaystyle \angle AOB $.
The formula for the length of an arc is:
$ \displaystyle l = \frac{\theta}{360^\circ} \times 2\pi r $