???? ??? ???? ????????? ??? ????? ??????? ???? ????? ?????? ???? ??? ???? ????????? ??? ????? ?? ???? ????? ???? ???? ???????? ????? ?????? ?????? ???? ???? ????????? ??? ????? ?? ???? ??????? ????? ????? ??????? ???? ????? ????? ???????: ???? ???? ????? ?????? ????? ?? ???? ??? ?????? ???????? ???? ????????? ??????. Is the proper angle 30 or