Tham khảo!
Program tich_chu_vi_dien_tich_hinh_tron;
uses crt; //Khai bao thu vien
var r,dien_tich,chu_vi:real; //Khai bao bien
begin
clrscr;
//Input:
write(‘Nhap ban kinh: ‘);readln(r);
//Output:
chu_vi:=r*2*pi;
dien_tich:=r*r*pi;
writeln(‘Chu vi: ‘,chu_vi:0:5);
writeln(‘Dien tich: ‘,dien_tich:0:5);
readln
end.