Unit error in equation

[odashnyam]

Hi I have an error message says

How could I deal with this error message. I added unit of temperature but it doesn't work.

Any suggestions, please.

[ms-4]

u have to put 17.78 mm whatever unit it has. . .

[-MFra-]

Assuming that T is a temperature, the equation is written like this:

[MikeArmstrong]

Please provide a worksheet.

Mike

[ValeryOchkov]

What must this formula return?