(1)56°23‘48“+16°35’43” (2)90°—28°12‘36“ (3)12°34’×4 (4)40°40
1个回答

度分秒属于60进制.

(1) 原式=(56°+16°)+(23'+35')+(48"+43")

=72°+58'+(1'31")

=72°59'31"

(2) 原式=89°59’60”-28°12'36"

=61°47'24"

(3) 原式=(12°×4)+(34'×4)=48°+(136')

=48°+(2°16‘)

=50°16'

(4) 原式=(40°/6)+(40'/6)

=(6又2/3)°+(6又2/3)'

=(6°40‘)+(6'40")

=6°46′40“

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