A sector is cut from a circle of radius $\displaystyle 21$ cm. The central angle of the sector is $\displaystyle 150$°. Find the length of the arc of this sector and the area of the sector.

\[\begin{aligned} \text { Length of the arc } & =2 \times \frac{22}{7} \times 21 \times \frac{150}{360} \\ & =55 \mathrm{~cm}^{2} \\ \text { Area of sector } & =\frac{22}{7} \times 21 \times 21 \times \frac{150}{360} \\ & =577.5 \mathrm{~cm}^{2} \end{aligned} \]