\documentclass{article}
\usepackage{pgf,tikz}
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\usepackage[width=17cm,right=2cm,height=24cm,top=2cm]{geometry}
\usepackage{unicode-math}
\usepackage{amsmath}
\usepackage{xepersian}
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\begin{document}
\begin{LTR}
$\angle A=\angle B$
\end{LTR}
\vspace{.75cm}

%
\begin{LTR}
$\frac{AB}{AC}=\frac{\sin C}{\sin B}\Longrightarrow \frac{\frac{AB}{AC}}{\frac{\sin C}{\sin B}}=1$
\end{LTR}
\end{document}