Geometry & Shapes (id: b640605c8)

本题目来源于试卷: Geometry & Shapes，类别为 IB数学

[填空题]
$\text { The triangle } A B C \text { is equilateral of side } 5 \mathrm{~cm} \text {. The point } D \text { lies on }[B C] \text { such that } D C=2 \mathrm{~cm} \text {. Find } \cos (C \hat{D A}) \text {. }$   

[/B C]

参考答案: -2.18±2%


本题详细解析:

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