why 21st if 2000 is 20th century??

The problem with C is that you expect float while it's impossible for float to have a precision you want in some cases. E.g. where area is > 100000.00
Because float is 7 decimal digits, so it won't work if you want +2 digits precision after the point. It's simply bigger than float could contain.
You should use double.

Expected 243607.12 (243607.125)
Submitted 243607.14 (243607.140625)

You see, it's 8 digits precision you want.
A more strange thing is that arc is double (???)
So, to solve this you have to use some obscure tricks which is not a good programming practice.

me with kyu 5 : interesting:)))

In C variation you doubled "const".
const char *CONST(here) haystack[]

It's impossible to drink that ridiculous amount of water. It gonna make all things worse.

I think it took me longer to figure out what you wanted from me than coding itself :D

is it a joke? your tests for c are broken

for matrix:
{
{0, 1, 2, 3, 45},
{10, 11, 12, 13, 14},
{20, 21, 22, 23, 24},
{30, 31, 32, 33, 34},
}

expected:
0,1,2,3,45
10,11,12,13,14
20,21,22,23,24
30,31,32,33,34

but got:
0,1,2,3,45
10,11,12,13,14
20,21,22,23,24
30,31,32,33,34

dude pls look at my solution i spent a few hours trying to make it work, had to COMPLETELY change the idea of the solution TWICE
yes i'm beginner but it's not a "beginner" exercise
i understand your logic, maybe in Python i'll do it much faster
but on C it's a nightmare, not even close to a beginner level