(a) 22 cm
Length of arc $= \dfrac{\theta}{360} \times 2\pi r = \dfrac{90}{360} \times 2 \times \dfrac{22}{7} \times 14 = \dfrac{1}{4} \times 88 = 22$ cm.
Use the formula: Length of arc $= \frac{\theta}{360} \times 2\pi r$. With $\theta = 90°$, $r = 14$ cm, and $\pi = \frac{22}{7}$, the factor $\frac{90}{360} = \frac{1}{4}$ simplifies calculation to give 22 cm. Remember this formula — it is directly stated in the Summary (point 1).