Question

Monthly expenditure of a person whose monthly salary is Rs 9,000 is shown in the adjoining figure. Find the amount he has (i) spent for food (ii) in his savings.

Answer 1

Let Rs 9,000 be represented by the area of the circle, i.e., $\pi r^2=9000$

(i) Area of sector AOB $=\frac{\theta }{{360}^{\circ }}\times \pi r^2$

$=\frac{{120}^{\circ }}{{360}^{\circ }}\times 9000=3,000$

Amount spent for food is Rs 3,000.

(ii) Area of sector $BOC=\frac{\theta }{{360}^{\circ }}\times \pi r^2$

$=\frac{{30}^{\circ }}{{360}^{\circ }}\times 9,000=750$

Amount saved in savings is $Rs750$.