34°25′×3+35°42′
=102°75′+35°42′
=137°117′
=138°57′
（180°-91°32′24″）÷3
=（180°59‘60’‘-91°32′24″）÷3
=89°27′36″÷3
=87°147′36″÷3
=29°49′12″