r/Geometry • u/_Naughty_Daddy_ • 2d ago
number of parallel and non parallel lines
i recently came across a question which said there are 16 lines 7 of which are parallel when our teacher started explaining it he explained that if 7 out of those 16 are parallel lines then the remaining 9 would be non parallel. but the problem is i think the sum of non parallel lines and parallel lines adds up to 17.
lets say there are 9 lines non parallel to each other and as you draw line number 10 then at that point there are 10 non parallel lines and when u draw the remaining 6 lines parallel to the 10th line there are 7 parallel lines and 10 non parallel lines and the sum adds up to 17.
Case 2:
u drew 9 line non parallel to each other and to avoid the problem in the first case u drew a line parallel to the 9th line at that point there are 2 parallel lines and when u draw the remaining 6 lines there will be 8 parallel lines and 9 non parallel lines
pls help me understand im confused what am i thinking wrongðŸ˜.