(1)
180°-(25°18′+65°56′)
=180°-90°74′
=179°60′-91°14′
=88°46′
(2)
(31°40′-25°4′30″)x3+28′3″x2
=(31°39′60″-25°4′30″)×3+56′6″
=6°35′30″×3+56′6″
=18°105′90″+56′6″
=18°161′96″
=18°162′36″
=20°42′36″
(1)
180°-(25°18′+65°56′)
=180°-90°74′
=179°60′-91°14′
=88°46′
(2)
(31°40′-25°4′30″)x3+28′3″x2
=(31°39′60″-25°4′30″)×3+56′6″
=6°35′30″×3+56′6″
=18°105′90″+56′6″
=18°161′96″
=18°162′36″
=20°42′36″