Parallel lines are always the same distance apart: they never meet. On drawings, parallel lines are shown with arrows. If there is more than one pair of parallel lines on a drawing, then the arrows are doubled up for the second pair.

Perpendicular lines are shown with a square for the angle, rather than a curve.

On a graph, are the lines `x=0` and `x=1` parallel or perpendicular?

`x=0` and `x=1` never meet, so the lines are parallel.

Answer: Parallel

A line CD is drawn at a right angle to the line AB. A second line is drawn at a right angle EF to the line AB. Are the lines CD and EF parallel?

Sketch the arrangement to see that the lines are parallel.

Answer: Yes

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