Imagine there is a country in which there are all important natural resources (oil, gas, metal ores, wood, etc.) in their natural form and which lies in a temperate climate region. There may be some portion of a sea. The country is completely isolated from the rest of the world - nothing (except for air, precipitation, etc.) can get in or out. What is the minimum population and size of the country to sustain a developed industrial society? (All the technology used there has to be produced somewhere in the country eventually.) The technology level is current. (Year 2014, realistic technologies that can be mass-produced with reasonable cost.)
By other words: What is the minimum amount of people and land to produce self-sustained agriculture and all relevant factories that are necessary for complete self sufficiency in industry from mining all ores to producing the final devices? Consider that people need to be educated and not all are geniuses that can be educated to the cutting-edge technology expert levels.
EDIT: You can assume the technology is initially present, it does not have to be invented, but next generation must be able to learn it and understand it. (For example people have a very good library, or computer database, as long as the computers are running.)