Question Video: Deciding Whether Two Straight Lines Are Perpendicular or Parallel

Video Transcript

Is line segment 𝐴𝐵 parallel or perpendicular to line segment 𝐵𝐶?

First, let’s highlight line segment 𝐴𝐵 there. And line segment 𝐵𝐶 is here. Line segment 𝐴𝐵 and line segment 𝐵𝐶 share an end point, point 𝐵. This is an intersection. And we know that parallel lines never intersect.

Line segment 𝐴𝐵 cannot be parallel to line segment 𝐵𝐶. We also know that, inside a rectangle, all four angles measure 90 degrees. The angle at their intersection is 90 degrees. And that confirms that line segment 𝐴𝐵 is perpendicular to line segment 𝐵𝐶.