You can make an equilateral triangle of side length 4 units (each side is made up of two radii from the circles), which you can use Heron's Formula to evaluate.
The shaded area is then the area of this triangle minus the areas of the three circular sectors inside that triangle.
Herons formula is not required. It provides a method to find the area of a triangle from the three sides but we are dealing here with 30-60-90 triangles where the area is readily calculated using the 2-1- rad3 relationship. prnceps solution has a typo error.Its 60/360 not 360/60 in the area for the three sectors.Google Herons formula to see it
Dear Mhmh96,
Heron's Formula for area of triangle given three sides
A=sq rt of s(s-a)(s-b)(s-c) where s= 1/2 of perimeter and in my opinion is the long way to find the area of an equilateral triangle. Princips uses the property of a 30-60-90 triiangle whch ought to be known by a geometry student but does not describe it that way