VBA macro that calculates slope based on two elevation points and a distance.

Hello,

I'm trying to write something in VBA that calculates slope based on two elevation points and a distance. All the information is given. I just want to click on the two elevation text values and then the dimension value to produce a percent value in text that I can place on the sheet. Can the value of a dimension be pulled into a variable?

Thanks in advance for your help.