我想知道“Console.WriteLine("该圆面积为{0}*{1}*{2:F2}={3:F3}",R,R,PI,a

我想知道“Console.WriteLine("该圆面积为{0}*{1}*{2:F2}={3:F3}",R,R,PI,area);“ 的{0}*{1}*{2:F2}=
string i;
double R,area;
double PI = 3.1415926;
Console.Write("请输入半径R：");
i = Console.ReadLine();
R = Convert.ToDouble(i);
area = R * R * PI;
Console.WriteLine("该圆面积为{0}*{1}*{2:F2}={3:F3}",R,R,PI,area);