To construct a line parallel to a given line through a point not on the line using paper folding you can perform the construction twice

Perpendicular. 

You form two parallel lines with an intersecting line passing through them. That's what was meant by 'through a point not on the line'. The point lies on another line, not on the line its parallel with. To give you a better visual, the figure is shown in the image (source:wikihow).

Yes, that is the correct formula. to solve this problem given the number of years, plug in the number of years for t and plug the whole thing into the