Question

Solve for the unknown side round the the nearest tenth.

Answer 1

Given:

$\begin{gathered} \angle A=22^{\circ} \\ b=13 \\ c=20 \end{gathered}$

To find a:

Using the cosine formula,

$\begin{gathered} a=\sqrt[]{b^2+c^2-2bc\cos A} \\ a=\sqrt[]{13^2+20^2-2(13)(20)\cos 22} \\ a=\sqrt[]{169+400-520\cos 22} \\ a=9.320 \\ a\approx9.3 \end{gathered}$

Hence, length of the unknown side is 9.3.