program dientich;
uses crt;
var r1,r2,r3:real;
{---CT-con---}
function dt(r:real):real;
begin
dt:=r*r*3.14;
end;
{---CT-chinh---}
BEGIN
clrscr;
write('Nhap ban kinh hinh tron thu nhat: '); readln(r1);
write('Nhap ban kinh hinh tron thu hai: '); readln(r2);
write('Nhap ban kinh hinh tron thu ba: '); readln(r3);
writeln('Dien tich hinh tron thu nhat la: ',dt(r1));
writeln('Dien tich hinh tron thu hai la: ',dt(r2));
writeln('Dien tich hinh tron thu ba la: ',dt(r3));
readln;
end.