[tex]\textit{using the pythagorean theorem} \\\\ c^2=a^2+b^2\implies \sqrt{c^2-a^2}=b \qquad \begin{cases} c=\stackrel{hypotenuse}{13}\\ a=\stackrel{adjacent}{5}\\ b=opposite\\ \end{cases} \\\\\\ \sqrt{13^2-5^2}=b\implies \sqrt{144}=b\implies 12=b[/tex]
