Program Hinh_tron;
Uses crt;
Var r,dt:real;
Begin
clrscr;
Writeln(' Nhap ban kinh hinh tron:');
Readln(r);
dt:= r*r*3.14;
Writeln('Dien tich hinh tron la:',dt);
Readln;
End.
Uses crt;
Var r:real;
Begin
clrscr;
Writeln('Nhap ban kinh hinh tron = '); Readln(r)
Write('Dien tich hinh tron la ',r*r*3.14:5:1);
Readln
End.