What is the difference between, parallel, perpendicular, and skew lines ?

Parallel lines never intersect.  They have the same slope and extend into infinity (picture 1).

Perpendicular lines do intersect.  At the intersection point, a 90° angle is formed (picture 2).

Skew lines are neither parallel nor intersecting.  They are on different planes (picture 3).

31 is prime. and it’s prime factorization is just 31.

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