Jawabanmu

Jawaban paling cerdas!
2014-07-12T14:41:47+07:00
2014-07-12T14:43:29+07:00
BC² = AC² + AB² - 2. AC . AB . cos A
9² = 10² + 7² - 2. 10.7 . cos
81 = 100 + 49 - 140 cos
140 cos = 149 - 81
cos = 68/140
cos A = 17/35 ≡ 0,485714285

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