I am having trouble with rounding up to 2 decimal places

Question

This is the code :

double b1 = double.Parse(Console.ReadLine());

double b2 = double.Parse(Console.ReadLine());

double h = double.Parse(Console.ReadLine());

double area = (b1 + b2) * h / 2;

double area1 = Math.Round(area, 2, MidpointRounding.ToEven);

Console.WriteLine(area1);

I have to round up the result, which means the variable "area" up to 2 decimal places. For example we have input (8, 13, 7) and the result is 73.5. What I want is the result to be 73.50. Please someone tell me what I am doing wrong.