The correct answer is:
22 cm, 231 cm²
Explanation:
Let $\mathrm{AB}$ be the given arc subtending an angle of $60°$ at the centre. Here, $\mathrm{r}=21\mathrm{cm}$ and $\theta =60°$
$\displaystyle \begin{array}{l}\text{Length of the arc ABC}=\dfrac{{2\pi r\theta {}^\circ }}{{360{}^\circ }}cm\\=\left( {2\times \dfrac{{22}}{7}\times 21\times \dfrac{{60{}^\circ }}{{360{}^\circ }}} \right)cm=\text{ }22cm\\\text{Area of the sector OACBO}=\dfrac{{\pi {{r}^{2}}\theta {}^\circ }}{{360{}^\circ }}\text{ c}{{\text{m}}^{2}}\\=\left( {\dfrac{{22}}{7}\times 21\times 21\times \dfrac{{60{}^\circ }}{{360{}^\circ }}} \right)c{{m}^{2}}=231\text{ c}{{\text{m}}^{2}}\end{array}$