(180°-91°31′24″)÷3 和78°21′45″×2-125°36′÷4

(180°-91°31′24″)÷3
=88°28‘36’‘÷3
=87°66’156‘’÷3
=29°22‘52’‘
78°21′45″×2-125°36′÷4
=156°42’90‘’-124°96‘÷4
=156°43’30‘’-31°24‘
=125°19’30‘’