http://www.flickr.com/photos/45632549@N03/8689569764/sizes/l/in/photostream/
要步驟
中三-數學 方位 20點
2013-04-29 7:32 am
回答 (3)
2013-04-29 8:01 am
✔ 最佳答案
1.答案是： D. 138 km
∠ABC = (205° - 180°) + (360°- 315°) = 70°
AB = 80 x 1.5 km = 120 km
BC = 60 x 2 km = 120 km
AC² = AB² + BC² - 2 x AB x BC x cos∠ABC (餘弦定律)
AC² = 120² + 120² - 2 x 120 x 120 x cos70° km
AC² = 18950 km
AC = 138 km
參考: 賣女孩的火柴
2013-04-30 2:07 am
AC² = AB² + BC² - (2 x AB x BC x cos∠ABC)
AC² = 120² + 120² - (2 x 120 x 120 x cos70° )
AC² = 1440 + 1440 - 2880 x cos70°
AC² = 18950
AC = 138
ans : 138
2013-04-29 18:08:14 補充：
ans:138km
AC² = 120² + 120² - (2 x 120 x 120 x cos70° )
AC² = 1440 + 1440 - 2880 x cos70°
AC² = 18950
AC = 138
ans : 138
2013-04-29 18:08:14 補充：
ans:138km
2013-04-29 8:33 am
AC² = AB² + BC² - (2 x AB x BC x cos∠ABC)
AC² = 120² + 120² - (2 x 120 x 120 x cos70° )
AC² = 1440 + 1440 - 2880 x cos70°
AC² = 18950
AC = 138
ans : 138
2013-04-29 00:34:13 補充：
ANS: 138 KM
AC² = 120² + 120² - (2 x 120 x 120 x cos70° )
AC² = 1440 + 1440 - 2880 x cos70°
AC² = 18950
AC = 138
ans : 138
2013-04-29 00:34:13 補充：
ANS: 138 KM
收錄日期: 2021-04-13 19:26:57
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130428000051KK00414