Concerning Circles $\quad]$ [Equilateral (Regular) Triangle]

Each of the three circles of radius $r$ touches the other two. Find the area of the figure located outside the circles and bounded by their arcs, enclosed between the points of tangency.
The desired area is equal to the difference between the areas of an equilateral triangle and three sectors.

## Answer

$r^{2}\left(\sqrt{3}-\frac{\pi}{2}\right)$