Question

Determine the length of the longest side of the triangle ABC. Showyour work and round answers to the nearest tenth. *15 in.CB78°10 in.A

Answer 1

We would make use of the cosine rule,

`\begin{gathered} C^2=A^2+B^2-2AB\cos C \\ C^2=15^2+10^2-2*10*15*\cos 78 \end{gathered}`
`\begin{gathered} C^2=325-62.374\text{ =262.626} \\ C=\text{ 16.206 }\approx\text{ 16.2 in} \end{gathered}`