The radii of two circles are 14 cm and 28 cm. If $π = \dfrac{22}{7}$ the area of the shaded portion is :

1. 1848 cm²

2. 1644 cm²

3. 486 cm²

4. 702 cm²

Area of shaded portion = Area of bigger circle - Area of smaller circle

$= π \times R^2 - π \times r^2\\[1em] = \dfrac{22}{7} \times 28^2 - \dfrac{22}{7} \times 14^2\\[1em] = \dfrac{22}{7} \times (28^2 - 14^2)\\[1em] = \dfrac{22}{7} \times (784 - 196)\\[1em] = \dfrac{22}{7} \times 588\\[1em] = \dfrac{12,936}{7}\\[1em] = 1,848 \text{ cm}^2$

The area of shaded portion is 1848 cm².

Hence, option 1 is the correct option.