Running EXE file with environment variable in path (PowerShell)

I want to run some executable on Windows using PowerShell. Path to this executable should be resolved with environment variable.

For example

running command

C:\Windows\system32\cmd.exe

as

$Env:SystemRoot\system32\cmd.exe

I have tried this option and it raises following exception

At line:1 char:16
+ $Env:SystemRoot\system32\cmd.exe
+                ~~~~~~~~~~~~~~~~~
Unexpected token '\system32\cmd.exe' in expression or statement.
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : UnexpectedToken

What is the right way to do it?

>Solution :

Tell the powershell to call the command by putting an ampersand in front &$Env:SystemRoot\system32\cmd.exe