documentclass[12pt]{article}
usepackage{mathtools,tcolorbox,tikz}
tcbuselibrary{skins}
begin{document}
begin{tcolorbox}[enhanced,colback=yellow!10!white,boxrule=0pt,frame hidden,
borderline north={1mm}{-1mm}{orange},borderline south={1mm}{-1mm}{orange}]
centering
$begin{array}{c|c}
b^{2} = a cdot b' & {displaystylefrac{1}{h^{2}} = frac{1}{b^{2}} + frac{1}{c^{2}}}\
c^{2} = a cdot c'
end{array}
$
end{tcolorbox}
end{document}