Question: Use Lagrange multipliers to find the indicated extrema

\[\begin{aligned} & \text{Minimize}\,\,\,\,\,f\left( x,y \right)=\sqrt{{{x}^{2}}+{{y}^{2}}} \\ & \text{s}\text{.t}\text{.}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2x+4y-15=0 \\ \end{aligned}\]