How to convert Decimal to Double in C#?

I want to assign the decimal variable trans to the double variable this.Opacity.
decimal trans = trackBar1.Value / 5000;
this.Opacity = trans;


When I build the app it gives the following error:
Cannot implicitly convert type decimal to double


An explicit cast to double like this isn't necessary:

double trans = (double) trackBar1.Value / 5000.0;

Identifying the constant as 5000.0 (or as 5000d) is sufficient:

double trans = trackBar1.Value / 5000.0;
double trans = trackBar1.Value / 5000d;

Stack Overflow Q#4, score: 539