If you mean y = 2x and y = 2x-1 then they are parallel lines because they have the same slope.
Straight lines.
Epithelium lines the ear
If you mean what type of triangle has perpendicular lines then it is right angle triangle.
Lines of least travel time.
contour lines
Parallel lines are two lines that will never intersect, like this.________________________________________________________
Straight lines.
EHV lines are type of electrical lines commonly used for experimentation in physics. They stand for 'Extra High Voltage' lines.
A _____ is a type of chord that consists of three pitches on consecutive lines or spaces.
Eight straight lines, meeting in pairs at eight vertices.
I would say curved lines.
Linear