Step 1
Draw the back yard.
Step 2
State cosine rule
[tex]a^2=c^2+b^2-2cb\cos A[/tex][tex]\begin{gathered} A=32.7^{\circ} \\ a=\text{ third side} \\ b=18.3 \\ c=12.1 \end{gathered}[/tex][tex]a=\sqrt[]{12.1^2+18.3^2-2(12.1)(18.3)(\cos 32.7)}[/tex][tex]\begin{gathered} a=\sqrt[]{146.41+334.89-372.6714649} \\ a=\sqrt[]{481.3-372.6714649} \\ a=\sqrt[]{108.6285351} \\ a=10.42250138 \\ a\approx10.42m\text{ to the nearest hundredth} \end{gathered}[/tex]Hence the length of the third side is approximately 10.42m to the nearest hundredth.
