How do I change a font size to be bigger than 72 pt.?

I have tried to change the size in the box next to drop down box and it will not change the size. I am highlighting the text before attempting to resize. Any ideas?How do I change a font size to be bigger than 72 pt.?
72 pt??!!!! That is HUGE! You'd get a few letters visible on the page when trying to compose or read an email. Did it occur to you that you can't go larger that 72? That is most likely the reason you aren't able to resize.