How to solve the first project in c# area of a circle

Question

I can't solve it

Answer 1

const double pi = 3.14;
double radius = 5;
double Area = pi * (radius * radius);

Convert.ToDouble(Area);
Console.WriteLine(Area);
Convert.ToDouble(radius);

Answer 2

this only gives me the output 78.5 like they asked for in the problem , but i only managed to get it by giving radius a value , i don't know how to make it input

Answer 3

it gave me a wrong output 12.56
it still don't solve the problem
with my code I could get the first test with the value 5
there is still 2 others
one with the value 6.4 and the last one with the value 10

Answer 4

solved thanks , if you could explain that to me It would be great ( i'm new to this Started only yesterday)

Answer 5

Hello how can I code. app