Video: Identifying Parallel and Perpendicular Lines

Complete using “parallel” or “perpendicular”: The two red-colored lines are _.

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Video Transcript

Complete using “parallel” or “perpendicular”: The two red-colored lines are what.

In this question, we’re given a picture of a shape, and two of its sides are colored red. Now, how can we describe these two red-colored lines? Are they parallel? Or are they perpendicular? We know that when two lines are parallel, they’re always the same distance apart. So if we think about this red line here to begin with, a line that’s parallel to this line might look like this, or even this. Or if we look at the red line at the bottom of our shape, a line that’s parallel to this might look like this or even this.

But when we look at the two lines together and compare them, we can see that they’re not parallel with each other at all, are they? Just like two railway tracks, parallel lines never touch. But we can see that these two lines do touch. In fact, where they meet, a little symbol’s been drawn. Do you remember what this symbol means? It’s the symbol we use to show a square corner or a right angle. And we know that the word we use to describe a pair of lines that meet at a right angle is “perpendicular.” These two sides of the shape meet at a right angle. And so we can say the two red-colored lines are perpendicular.

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