\documentclass[fontsize=16pt]{scrbook}
\usepackage[left=1.00cm, right=1.00cm, top=1.00cm, bottom=1.00cm]{geometry}
\usepackage{amsmath,amsfonts,amssymb}
\usepackage{tabularx,tabulary}
\usepackage{graphicx}
\usepackage{booktabs}

\usepackage{tcolorbox}
\tcbuselibrary{skins}
\tcbuselibrary{breakable}

\usepackage{setspace}

\usepackage{fontspec}
\usepackage{polyglossia}

\setmainlanguage{english}
\setotherlanguage{arabic}

\newfontfamily\arabicfont[Script=Arabic,Scale=1.1]{Amiri}
\renewcommand{\theequation}{\arabic{equation}}

\makeatletter
\def\tagform@#1{\maketag@@@{\normalfont\upshape(#1)}} % Ensure equation numbers are always upright
\makeatother

\newtcolorbox{myremark}[1]{%
	attach boxed title to top right={yshift=-2mm},
	coltitle=black,colbacktitle=red!45!white,enhanced,
	fonttitle=\bfseries,
	title=#1,
	colframe=red!75!black,
	colback=yellow!80,
}


\newtcolorbox{definition}[1]%
{ enhanced,arc=1mm,outer arc=1mm,
	attach boxed title to top right={yshift=-2mm},
	colframe=blue!50!black,colback=green!15!white,
	coltitle=blue!50!black,colbacktitle=yellow!50!white,
	title=#1,
}

\newtcolorbox{proposition}[1]%
{ enhanced,arc=1mm,outer arc=1mm,
	attach boxed title to top right={yshift=-2mm},
	colframe=red!80!blue,colback=blue!15!white,
	coltitle=red!80!blue,colbacktitle=red!30!white,
	title=#1,
}

\newtcolorbox{myexample}[1]{%
	empty,
	attach boxed title to top right={yshift*=-\tcboxedtitleheight},
	title={#1},
	boxed title style={
		overlay={
			\draw[green!70!blue,line width=2pt,] (frame.south west)--(frame.south east);
		},
		size=minimal, top=0pt, left=0pt
	},
	coltitle=red!10!blue,
}




\begin{document}
\begin{center}
	hello \textarabic{السلام عليكم} how are you
\end{center}

\begin{myremark}{\textarabic{ملاحظة}}
	\begin{Arabic}
	مثال على الرياضيات باللغة العربية \\
	ارقام المعادلات بين قوسين بشكل صحيح
	\end{Arabic}
	\begin{equation}
		\frac{d}{dx}(\sin x) = \cos x
	\end{equation}
\end{myremark}

\begin{proposition}{\textarabic{خاصية}}
	\begin{Arabic}
		مثال على الرياضيات باللغة العربية
	\end{Arabic}
	\begin{equation}
		2x^2-3x+2 = 0
	\end{equation}
\end{proposition}

\begin{definition}{\textarabic{تعريف}}
	\begin{Arabic}
		مثال على الرياضيات باللغة العربية
	\end{Arabic}
	\begin{equation}
		\frac{d}{dx}(\sin x) = \cos x
	\end{equation}
\end{definition}

\begin{myexample}{\textarabic{مثال}}
	\begin{Arabic}
		مثال على الرياضيات باللغة العربية
	\end{Arabic}
	\begin{equation}
		\frac{d}{dx}(\sin x) = \cos x
	\end{equation}
\end{myexample}
	
\end{document}