Question

初一数学， 30°25×3等于多少？ 48°39'+67°31'

Answer 1

30°25×3 分成2步，先计算分25'x3 = 75'=1°15'，再计算度30x3=90度，再加 1°15' = 91°15'

48°39'+67°31'同理
=(48°+67°) + (39'+31')
=115°+70'
=116°10'

追问

麻烦还有一个90°－78°19'23″ 我个高中生被我妹妹初一的数学角度转换难住了

追答

90°－78°19'23″ 其实和平常的加减法一样，只不是度分秒间的进制是60

=(89°+60') - 78°19'23'
= (89°-78°) + (60'-19'23'')
=11°+ (59'+60'' - 19'23'')
=11°+(59'-19') +(60''-23'')
=11°+40' + 37''
=11°40'37''