Solutions are due before midnight ET the Monday following the week of the problem. This will sometimes be extended to Tuesday in the case of a holiday, and a full calendar will be available soon. When students submit a solution, they'll receive an automated reply via email thanking them for their submission, and giving them the address of a page they can go to in order to correct their solution. They should NOT submit another solution. A few sample student solutions will be posted the Friday following the week of the problem.
Students can include a gif or a jpg file when they submit their solution.
The directions are on the submit pages. Sketchpad, Cabri, and other file formats are not currently supported, but we're hoping to allow those at some point this year. You can read more about appropriate solutions on our Rules page. The Geometry Problem of the Week is used in a lot of different ways. Some teachers preview the problem and assign it to the students if it fits in with the current topics they're covering.