Side c

In △ABC a=2, b=4 and ∠C=100°.

Calculate length of the side c.

Correct answer:

c =  4.77

Step-by-step explanation:

$$\begin{gathered} c^2=a^2+b^2-2ab\cos 100^{\circ } \\ c=\sqrt{2^2+4^2-2\cdot 2\cdot 4\cdot \cos 100^{\circ }}=4.77 \end{gathered}$$

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