Câu 1
Program Chu_nhat;
uses crt;
Var a, b, S, CV: real;
Begin  
 Write('Nhap chieu dai:'); readln(a);    
 Write('Nhap chieu rong:'); readln(b);  
   S := a*b;    
 CV := (a+b)*2;
 Writeln('Dien tich hinh chu nhat la:',S);
 Writeln('Chu vi hinh chu nhat la:',CV:10:2);  
 readln;
end.