Identify parallel lines

Parallel lines are distinct straight lines in the same plane that run in the same direction and never intersect; the distance between them remains constant, and they may be horizontal, vertical, or slanted. This understanding includes identifying parallel sides or line segments in diagrams, grids, and familiar polygons, regardless of their lengths, but does not include slope calculations, equations, or proofs involving transversals.

Detailed Explanation: Identify parallel lines

Parallel lines are straight lines that:

go in the same direction,
stay the same distance apart, and
never meet.

They can be horizontal, vertical, or slanted. Parallel sides do not have to be the same length.

Example: Look at rectangle $(ABCD)$ .

A -------- B
|          |
|          |
D -------- C

Find the pairs of parallel sides.

Step 1: Check the horizontal sides.
Side $\overline{AB}$ and side $\overline{DC}$ both go from left to right. They stay the same distance apart, so they are parallel.

\overline{AB} \parallel \overline{DC}

Step 2: Check the vertical sides.
Side $\overline{AD}$ and side $\overline{BC}$ both go up and down. They stay the same distance apart, so they are parallel.

\overline{AD} \parallel \overline{BC}

So the pairs of parallel sides are $\overline{AB}$ and $\overline{DC}$ , and $\overline{AD}$ and $\overline{BC}$ .

To identify parallel lines, look for lines that point in the same direction and remain equally spaced.

Learn by doing: Identify parallel lines

Click a topic below to practice the foundational skills you'll need, learn the steps, or master this skill

Practice with unlimited practice problems

Slope - Find Parallel - Graph to Graph

Earned ?

Identify parallel lines

Detailed Explanation: Identify parallel lines

Learn by doing: Identify parallel lines

Practice with unlimited practice problems

Practice:

Slope - Find Parallel - Graph to Graph