Four circular coasters, each of radius 7 cm, lie flat on a table. Each touches the two next to it, and their centres form a square. What is the area of the space enclosed between the four coasters? Take $\pi = \frac{22}{7}$.

Explanation

1. 01

   The centres are $7 + 7 = 14$ cm apart, so they form a square of side 14 cm, area 196 cm².

2. 02

   Each corner of the square holds a quarter of a coaster, so the four quarters make one full circle: $\frac{22}{7} \times 7 \times 7 = 154$ cm².

3. 03

   Enclosed space = $196 - 154 = 42$ cm².