🎮 Games › 🎬 Lesson videos › Parallel and Perpendicular LinesParallel and Perpendicular Lines
⏱ 0:23 📘 Grade 4 · Parallel and perpendicular
Two lines on a flat surface that never meet are parallel; lines that cross at a right angle are perpendicular, meeting at the foot of the perpendicular.
The videos are narrated in Mandarin Chinese with on-screen subtitles.
📚 What you will learn
In the same plane, two lines either cross or never meet . Lines that never meet are parallel : each is a parallel line of the other. Lines that cross at a right angle are perpendicular ; the crossing point is the foot of the perpendicular.
🎙️ What the video says (in Chinese)
同一个平面里的两条直线，有哪些位置关系？我们来转一转！ 不相交的两条直线互相平行，一条是另一条的平行线。 转一转，两条直线相交了。相交成直角，就叫互相垂直，交点叫垂足。 不相交是平行，相交成直角是垂直！
✏️ Try it yourself
The two edges of a ruler: parallel or perpendicular?
Show answer Parallel
Two lines cross at 60°. Are they perpendicular?
Show answer No, only a 90° crossing is perpendicular.
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