R1 30 Degree G Scale Radius Curved Track, 1 Piece

The listing says it's for 12 pieces, is that correct?

With these 12 pieces of track, what diameter will the resulting circle of track be?

If i want to circle a 12' x 12' room's perimeter with track, what do i need? i already have the starter set circle of track from years ago. thank you.

Does one of the pieces have the hookup for electrification of the track?