var a,b,s:integer; c:word; begin write('nhap avà b '); read(a,b); s:=a*b*1/2; c:=(a+b)*2; writeln('dien tich la ' s ); write('chu vi la 'c); readln end
#include <bits/stdc++.h>
using namespace std;
double a,b,c;
int main()
{
cin>>a>>b;
c=sqrt(a*a+b*b);
cout<<fixed<<setprecision(2)<<a+b+c<<endl;
cout<<fixed<<setprecision(2)<<a*b/2<<endl;
return 0;
}