Cross Multiplication with Arrows

Question

I am trying to find help on how to reproduce the following image. I don't have much for a minimal example except:

\documentclass{article}
\usepackage{amsmath,mathtools}
\begin{document}
\begin{align*}
\dfrac{3}{5}&=\dfrac{4.50}{x}\\
          3x&=5(4.50) &&\textcolor{blue}{\text{Set cross products equal}}
\end{align*}
\end{document}

Here is an image of what I want:

Can someone help?

Answer 1

Here is a proposal. Normally one could get rid of the darker region at the intersection by dialing transparency group, but for some reason this makes here the arrows disappear.

\documentclass{article}
\usepackage{amsmath,mathtools}
\usepackage{tikz}
\usetikzlibrary{tikzmark,calc,shapes.arrows}
\begin{document}
\begin{align*}
\tikzmark{f1}\dfrac{3}{5}&=\dfrac{4.50}{x}\tikzmark{f2}\\
          3x&=5(4.50) &&\textcolor{blue}{\text{Set cross products equal}}
\end{align*}
\begin{tikzpicture}[overlay,remember picture]
\begin{scope}[opacity=0.2]
\begin{scope}[blend mode=multiply]
\path let 
\p1=($([yshift=4mm,xshift=3mm]pic cs:f2)-([yshift=-2mm,xshift=-3mm]pic cs:f1)$),
\n1={veclen(\x1,\y1)} in
([yshift=-2mm,xshift=-3mm]pic cs:f1) -- ([yshift=4mm,xshift=3mm]pic cs:f2)
node[fill=blue,midway,sloped,single arrow,minimum height=\n1]{};
\path let 
\p1=($([yshift=4mm,xshift=-3mm]pic cs:f1)-([yshift=-2mm,xshift=3mm]pic cs:f2)$),
\n1={veclen(\x1,\y1)} in
([yshift=-2mm,xshift=3mm]pic cs:f2) -- ([yshift=4mm,xshift=-3mm]pic cs:f1)
node[fill=blue,midway,sloped,single arrow,minimum height=\n1,
shape border rotate=180]{};
\end{scope}
\end{scope}
\end{tikzpicture}
\end{document}