A chord of a circle of radius 10 cm subtends 90° at the centre. Find the area of the corresponding:

(A) minor sector (that subtends 90° at the centre), and

(B) major sector (that subtends 270° at the centre). (Use $\pi = 3.14$.)                                                       [Page No. 148]

Given, Radius = 10 cm

(A) Minor sector ($90^\circ$):

$$\begin{aligned} \text{Area} &= \pi r^2 \times \frac{\theta}{360^\circ} = 3.14 \times 100 \times \frac{90}{360} \\ &= 3.14 \times 100 \times \frac{1}{4} = 78.5 \text{ cm}^2 \end{aligned}$$

(B) Major sector ($270^\circ$):

$$\begin{aligned} \text{Area} &= 3.14 \times 100 \times \frac{270}{360} \\ &= 3.14 \times 100 \times \frac{3}{4} = 235.5 \text{ cm}^2 \end{aligned}$$