Take a screenshot and run it through <a href="https://www.myfonts.com/WhatTheFont" rel="nofollow">https://www.myfonts.com/WhatTheFont</a>.
One way is to copy a word from that part of the PDF document, and paste it into Word or another rich text editor. Then click in the middle of the pasted word. The editor's font display will show you the name of the font.<p>There is a Lin/Win/Mac font tool here <a href="http://www.foolabs.com/xpdf/download.html" rel="nofollow">http://www.foolabs.com/xpdf/download.html</a>