84°40' 30" - 47°30' / 6 + 4°12' 50" X 3
= 84°40' 30" - (42°+ 5°+ 30' ) / 6 + (4°+ 12' + 50" ) X 3
= 84°40' 30" - (42°/ 6 + 300' / 6 + 30' / 6) + (12°+ 36' + 150")
= 84°40' 30" - (7°+ 50' + 5') + 12°38' 30"
= 96°78' 60" - (7°+ 55')
= 96°79' - 7°55'
= 89°24