program bai1;

Uses crt;

Var

         a,b:integer;

Begin

    Clrscr;

        writeln('a, Chu vi hinh chu nhat la: ',(4+5)*2);

        writeln('    Dien tich hinh chu nhat la: ',4*5);

        writeln('b, ');

        write('Nhap chieu dai: '); readln(a);

        write('Nhap chieu rong: '); readln(b);

        writeln('Chu vi hinh chu nhat la: ',(a+b)*2);

        write('Dien tich hinh chu nhat la: ',a*b);

        Readln;

End.

*E không hiểu chỗ nào thì hỏi lại nhé

#HNgoc

#Chuc_em_hoc_tot

a)

Program baitap;

Uses crt;

Begin

Clrscr;

Writeln('Dien tich HCN:', 4*5);

Writeln('Chu vi HCN:', (4+5)*2);

Readln

End.

b)

Program baitap;

Uses crt;

Var a,b:real;

Begin

Clrscr;

Write('Nhap chieu dai va chieu rong:');

Readln(a,b);

Writeln('Dien tich HCN:', a*b);

Writeln('Chu vi HCN:', (a+b)*2);

Readln

End.