Calculate the area of a regular hexagon with a side length of 20 cm.

The road sign is in the shape of a regular hexagon.
The side length of the hexagon is $s = 20$ cm.

The area $A$ of a regular hexagon with side length $s$ is given by the formula:

Substitute $s = 20$ cm into the formula:

First, calculate $20^2$:

Multiply $\frac{3\sqrt{3}}{2}$ by 400:

To provide a numerical value, use $\sqrt{3} \approx 1.732$:

The area of the road sign is approximately 1039.2 cm$^2$.