#include <stdio.h>
#include <math.h>
struct side{
int a;
int b;
int c;
};
int main(void) {
struct side sankaku={5,5,5};
double s,K;
s=(sankaku.a+sankaku.b+sankaku.c)/2.0;
K
=sqrt(s
*(s
-sankaku.
a)*(s
-sankaku.
b)*(s
-sankaku.
c));
return 0;
}
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