C# "Area of a Circle" Test Cases?

Question

I'm kinda confused with the output for the test cases. I go with:

double Radius = Convert.ToDouble(Console.ReadLine());
double Area = Math.PI * Radius * Radius;

Which is working great but the output seems to be slighty different for every test case. Is there something I'm not thinking of right now?
Example: "Input 5, expected output 78.5"
THEN "Input 6.4, expected output 128.6144" and so on.

I'm trying different things like Math.Round or Convert.ToSingle but I don't see a solution to pass every test case at once. One case doesn't even display decimal numbers. What do I miss?

Answer 1

Aleks Weyand , it's written in the task description "the program declares a constant pi => 3.14". Instead of this you are using Math.PI which has more numbers after the decimal point, that's why the result is not the same.

Answer 2

I think in that test u need to declare pi,
try using,

const double pi = 3.14

Answer 3

I just changed it to:

double Area = pi * Radius * Radius;

Now it's working fine. Thank you guys.