var
  SKRUGA, SSEKTORA, SSEGMENTA, R, BETA, ALFA : Real;
  
procedure TForm1.KrugClick(Sender: TObject);
begin
   R:=StrToFloat(Edit1.Text);
   SKRUGA:=pi*R*R;
   Edit4.Text:=FloatToStr(SKRUGA);
end;

procedure TForm1.SectorClick(Sender: TObject);
begin
  BETA:=StrToFloat(Edit2.Text);
  SSEKTORA:=pi*R*R*BETA/360;
  Edit5.Text:=FloatToStr(SSEKTORA);
end;

procedure TForm1.SegmentClick(Sender: TObject);
begin
  ALFA:=StrToFloat(Edit3.Text);
  SSEGMENTA:=R*R/2*(pi*ALFA/180-SIN(ALFA));
  Edit6.Text:=FloatToStr(SSEGMENTA);
end;

procedure TForm1.Edit1Enter(Sender: TObject);
begin
  Edit1.Color:=clYellow;
end;

procedure TForm1.Edit1Exit(Sender: TObject);
begin
  Edit1.Color:=clWhite;
end;

end.