Triangle.equilateral constructor
Creates an equilateral triangle inscribed in a circle with given
center and radius.
Implementation
factory Triangle.equilateral(
{required Point center, required double radius}) {
Point a = center.pointAtAngle(radius, 0);
Point b = center.pointAtAngle(radius, 2 * pi / 3);
Point c = center.pointAtAngle(radius, 4 * pi / 3);
return Triangle(a, b, c);
}