Calculate the side of a regular triangle, circumscribed about a circle with a radius of 3 cm.

A triangle is called regular if all sides are equal.
If the triangle is equilateral, then the radius of the circle inscribed in the triangle is determined by the formula:
r = a / (2 * √3), where a is the side of the triangle.
Let us express from this formula a:
a = r * 2 * √3
Substitute the numbers:
a = 3 * 2 * √3 = 6 * √3
Answer: the side of the triangle is 6 * √3 cm. Or 10.39 cm.