Apple 27″ iMac (Late 2012) has a pixel density of:
108.79

A.K.A. 27-inch
Released: 2012

Resolution: 2560×1440 27″ display

Quad HD (QHD) 2560×1440, 16:9 aspect ratio

Totaling 3.69mp (megapixels) and having a PPI of 108.79

Category: Desktop LCD
Tags:

iMac

The front face of a unibody Intel-based iMac
Developer	Apple Inc.
Manufacturer	Apple Inc.
Product family	Macintosh
Release date	PowerPC-based August 15, 1998; 21 years ago (1998-08-15) (G3) January 7, 2002; 17 years ago (2002-01-07) (G4) August 31, 2004; 14 years ago (2004-08-31) (G5) Intel-based January 10, 2006; 13 years ago (2006-01-10) (plastic) August 7, 2007; 12 years ago (2007-08-07) (aluminum) October 20, 2009; 9 years ago (2009-10-20) (unibody) November 30, 2012; 6 years ago (2012-11-30) (slim unibody) October 16, 2014; 4 years ago (2014-10-16) (slim unibody with Retina 5K display) December 14, 2017; 20 months ago (2017-12-14) (iMac Pro)
Operating system	Mac OS 8 Mac OS 9 macOS (Previously known as Mac OS X, OS X)
Related articles	Mac Mini, Mac Pro, iMac Pro
Website	Apple – iMac

This righthand infobox courtesy of Wikipedia.