In the given figure, chord AB subtends an angle of 120° at the centre of the circle with radius 7 cm. Find (i) perimeter of major sector OACB, and…

(i) Perimeter of major sector = length of major arc ACB + $\displaystyle 2$ × radius \[\begin{aligned} & =\frac{(360-120)}{360} \times 2 \times \frac{22}{7} \times 7+2 \times 7 \\ & =\frac{130}{3} \mathrm{~cm} \text { or } 43.3 \mathrm{~cm} \end{aligned} \]

(ii) Area of shaded segment = Area of minor sector - Area of \(\displaystyle \triangle \mathrm{OAB}\) \[\begin{aligned} & =\frac{120}{360} \times \frac{22}{7} \times 7 \times 7-21.2 \\ & =30.1 \mathrm{~cm}^{2} \end{aligned} \] So, area of shaded segment is \(\displaystyle 30.1 \mathrm{~cm}^{2}\).