Question

how to find if line is parallel or perpendicular

Answer 1

Parallel lines are two lines that are always the same distance apart and never touch. In order for two lines to be parallel, they must be drawn in the same plane, a perfectly flat surface like a wall or sheet of paper. ... Any line that has the same slope as the original will never intersect with it.
Perpendicular means "at right angles". A line meeting another at a right angle, or 90° is said to be perpendicular to it. In the figure above, the line AB is perpendicular to the line DF. If they met at some other angle we would say that AB meets DF 'obliquely'.