Question: How many different PPI does the model with ppcm of 87 have?
SQL: SELECT COUNT("PPI (pixels per inch )") FROM "1-27653752-1" WHERE "ppcm (pixels per cm )" = 87.0;

Question: What's the resolution of the model with a PPD of 69?
SQL: SELECT "Resolution" FROM "1-27653752-1" WHERE "Pixels per degree (PPD)" = 69.0;