#include<iostream>
using namespace std;

double polet(double a, double b, double h){
    return 0.5*(a+b)/h;
}

double obwodt(double a, double b, double c, double d){
    return a+b+c+d;
}

int main() {
    cout<<"Pole trapezu:\n";
    cout<<polet(8.4,5.2,3.0)<<"\n";

    cout<<"Obwód trapezu:\n";
    cout<<obwodt(8.4,5.2,4.0,5.0)<<"\n";

    return 0;
}