Tablets loaded with Google Play for Education launched today, with a focus on K-12 schools in the United States.

Google Play is a destination where schools can find teacher-approved, educational apps and videos. It has been in beta testing in 50 schools, and in September, we wrote about the experience of one of the testing districts—Hillsborough Township schools in New Jersey.

The suite of educational resources is being delivered on three different-sized tablets: the 7-inch Nexus 7, which is available now; or the 8-inch HP Slate 8 Pro or the 10-inch ASUS Transformer Pad, both of which will be available early next year. The Nexus is priced at $229 with a $30 management charge per tablet.

The user experience is geared to educator decisionmakers: In fact, teachers can pay using a purchase order via the device.

Rick Borovoy, product manager for Google Play for Education, wrote in a blog that more than 30 million people use Google Apps for Education.

The newly released Google Play for Education will be competing against Apple’s iPad and all the education apps in its universe, and relative newcomer Amplify. Last week, we reported that iPads command 94 percent of the tablet market.