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中三-數學 方位 20點

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http://www.flickr.com/photos/45632549@N03/8689569764/sizes/l/in/photostream/ 要步驟

最佳解答:

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

其他解答:

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 = 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 KM63D0B758E2D502CC
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