89°59′60〃- 60°13′15〃= 29°46′45〃
∠a =( 179°59′60〃- 60°13′15〃）+30°
=119°46′45〃+ 30°
=149°46′45〃
60度13分15秒角的余角是?若角a比它的补角大30度,则角a等于多少度?
89°59′60〃- 60°13′15〃= 29°46′45〃
∠a =( 179°59′60〃- 60°13′15〃）+30°
=119°46′45〃+ 30°
=149°46′45〃