Random _random = new Random();
private Vector3 RandomPointInCircle(Vector3 position, float radius)
{
float randomRadius = radius * (float)Math.Sqrt(_random.NextDouble());
double randomAngle = _random.NextDouble() * MathHelper.TwoPi;
float x = randomRadius * (float)Math.Cos(randomAngle);
float z = randomRadius * (float)Math.Sin(randomAngle);
return new Vector3(position.X + x, position.Y, position.Z + z);
}