.what is the resolution on a MacBook Pro 15 inch retina

MEMORY

Built-in Memory 8 or 16 GB PC3-12800 (1600 MHz) DDR3L on-board memory

Maximum Memory 16 GB

Memory Slots None

Interleaving Support Yes

DISPLAY

Built-in Display 15.4-inch (diagonal) LED-backlit display with IPS technology at 220 pixels per inch

Resolutions 2880 by 1800 pixels (Retina); scaled resolutions: 1920 by 1200, 1680 by 1050, 1280 by 800, and 1024 by 640 pixels

GRAPHICS

Graphics Card NVIDIA GeForce GT 650M and Intel HD Graphics 4000

Graphics Memory 1 GB GDDR5 (GeForce GT) 512 MB DDR3 (HD Graphics) shared with main memory

Display Connection 1 - HDMI port or Thunderbolt digital video output (Supports an HDMI-compatible device while using one Thunderbolt display or support for two Thunderbolt displays)

Display Modes Dual display extended, video mirroring, and AirPlay Mirroring

External Resolution Up to 2560 by 1600 pixels on up to two external displays

Camera 720p FaceTime HD camera

Use this to access all the resolutions

http://www.madrau.com/indexSRX4.html

The maximum resolution of your MacBook Pro with Retina display is 2880x1800. Apple decided to set up the Displays preference pane on the MacBook Pro with Retina display in order to choose a more Retina or less Retina resolution. See > http://www.everymac.com/systems/apple/macbook_pro/macbook-pro-retina-display-faq /macbook-pro-retina-display-hack-to-run-native-resolution.html