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中二數學問題
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圖片：http://upload.u-discuss.net/file/20070818191331.JPG問題一：in the figure , a lazy cat slept on a platform h m from the ground. AB,AC,DC are the pillars of the platform, where AB''_I_''AC and BC ''_I_''CD.a. find the length of BC.b. find the area of... 顯示更多 圖片：http://upload.u-discuss.net/file/20070818191331.JPG 問題一：in the figure , a lazy cat slept on a platform h m from the ground. AB,AC,DC are the pillars of the platform, where AB''_I_''AC and BC ''_I_''CD. a. find the length of BC. b. find the area of triangle ABC. c. find the value of h.
最佳解答:
You did not mark point D but I think it should be the point where the cat sleeps. a) BC^2 = 12^2 + 16^2 ( Pyth. theorem ) BC^2 = 400 BC = 20 Hence BC is 20m. b) Area = AC x AB / 2 = 16 x 12 / 2 = 96m^2 c) AB / AC = tan ∠ACB 12 / 16 = tan ∠ ACB ∠ ACB = 36.8699* As BC ┴ CD, ∠ ACD = 90* - 36.8699* = 53.1301* cos ∠ ACD = h / 16 cos 53.1301* = h / 16 h = 9.6
應該係 b
中二數學問題
發問:
圖片：http://upload.u-discuss.net/file/20070818191331.JPG問題一：in the figure , a lazy cat slept on a platform h m from the ground. AB,AC,DC are the pillars of the platform, where AB''_I_''AC and BC ''_I_''CD.a. find the length of BC.b. find the area of... 顯示更多 圖片：http://upload.u-discuss.net/file/20070818191331.JPG 問題一：in the figure , a lazy cat slept on a platform h m from the ground. AB,AC,DC are the pillars of the platform, where AB''_I_''AC and BC ''_I_''CD. a. find the length of BC. b. find the area of triangle ABC. c. find the value of h.
最佳解答:
You did not mark point D but I think it should be the point where the cat sleeps. a) BC^2 = 12^2 + 16^2 ( Pyth. theorem ) BC^2 = 400 BC = 20 Hence BC is 20m. b) Area = AC x AB / 2 = 16 x 12 / 2 = 96m^2 c) AB / AC = tan ∠ACB 12 / 16 = tan ∠ ACB ∠ ACB = 36.8699* As BC ┴ CD, ∠ ACD = 90* - 36.8699* = 53.1301* cos ∠ ACD = h / 16 cos 53.1301* = h / 16 h = 9.6
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其他解答:應該係 b
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