Find the area of a quadrant of a circle whose circumference is 44 cm.                                                        [Page No. 148]

Circumference = 44 cm

$$\Rightarrow 2\pi r = 44$$

$$\Rightarrow r = \frac{44}{2 \times \frac{22}{7}}$$

$$= \frac{44 \times 7}{44} = 7 \text{ cm}$$

$$\text{Area of full circle} = \pi r^2$$

$$= \frac{22}{7} \times 49 = 154 \text{ cm}^2$$

$$\text{Area of quadrant} = \frac{1}{4} \times 154 = 38.5 \text{ cm}^2$$

Caution
Students should not confuse circumference with area. Circumference (perimeter) uses $2\pi r$ while area uses $\pi r^2$; using the wrong formula is a frequent mistake.