Get and set angle/rotation on runtime in Silverlight

I would like to request some help, because I'm getting crazy I already have tried the following:

var t = (CompositeTransform)var OriginalAngle = t.Rotation;

and

var _originalAngle = (double)RenderTransform.GetValue(RotateTransform.AngleProperty);

But I'm getting exceptions.

I trying to obtain the rotation angle on a constructor, I don't know if make any difference.

Try adding a name to the RotateTransform.

<Rectangle  Name="rectangle1" Stroke="Black" StrokeThickness="1" >
        <Rectangle.RenderTransform>
            <RotateTransform x:Name="myAngle" Angle="90" />
        </Rectangle.RenderTransform>
</Rectangle>

Then to access it through code just use myAngle.Angle