Tham khảo :
program tinh_dien_tich_chu_vi;
uses crt;
var a,b,s,cv:real;
begin
clrscr;
write('nhap do dai canh a: ');readln(a);
write('nhap do dai canh b: ');readln(b);
cv:=(a+b)*2;
s:=a*b;
writeln('chu vi cua nhinh chu nhat la: ',cv,' va dien tich cua hinh chu nhat la: ',s);
readln;