If the side length of equilateral △ ABC is 3cm, the radius of its inscribed circle is

If the side length of equilateral △ ABC is 3cm, the radius of its inscribed circle is

The inscribed circle of an equilateral triangle,
The distance from the center of the circle to the three sides is equal,
The set of points with equal distance to both sides of the triangle is the angular bisector of the triangle,
So the center of the circle is at the intersection of the three bisectors of the triangle,
In an equilateral triangle, the bisector of an angle coincides with the height and the center line
So the radius of the circle is one third of the height of the triangle,
R = root 3