I already know how to do it in wpf as
<TextBlock HorizontalAlignment="Left" Margin="359,10,0,0"
TextWrapping="Wrap" VerticalAlignment="Top" Width="75">
<Run>X</Run>
<Run BaselineAlignment="Superscript" FontSize="8">4</Run>
</TextBlock>
or this answer, or in the code as
string area;
area = "mm\xB2";
testTblock.Text = area;
But how you can do it in Application.Resources? As
<Application.Resources>
<System:String x:Key="area">
//what should be here?
</System:String>
so that I could apply it to the DynamicResource as
<TextBlock Text="{DynamicResource area}" />