Lines, Rays, and Line Segments: Look at the Ends
3-5
1
Parallel and Perpendicular Lines: Do They Cross?
Lesson Details
Grade Level
3-5
Duration (minutes)
1
Summary
Students learn to name a pair of lines by asking two questions: do the lines cross, and if so, do they make a square corner? Parallel lines never cross and stay the same distance apart. Intersecting lines cross at one point. Perpendicular lines cross at a right angle (90°), marked with a small square. A quick-check round shows that lines can point any direction and keep their names.
Student Worksheet: Parallel and Perpendicular Lines
Teacher Note: Students can watch the video lesson above and answer the questions. Click the “Teacher Answer Key” dropdown below when you are ready to review the solutions!
Key Concepts:
• Parallel Lines: Never cross. They stay the same distance apart forever.
• Intersecting Lines: Cross at one point.
• Perpendicular Lines: Cross and make a square corner, a right angle of exactly 90°. The corner is marked with a small square.
• Any Direction: Lines can be tilted or turned and still keep the same name.
Instructions: Read each question carefully and write your answer in the space provided.
- Question 1: What do we call two lines that never cross?
- Question 2: Railroad tracks are an example of which kind of lines?
- Question 3: What is the difference between intersecting lines and perpendicular lines?
- Question 4: How many degrees are in the corner made by perpendicular lines? How do we mark it?
- Question 5: Two lines are turned so they look like the letter X, and they make a square corner. Are they parallel, intersecting, or perpendicular? Explain.
- Question 6: Challenge: Look at the letter H. Name one pair of parallel lines and one pair of perpendicular lines in it.
Click to reveal Teacher Answer Key
1. Parallel lines. @ 0:10
2. Parallel lines. @ 0:13
3. Intersecting lines cross at one point at any angle. Perpendicular lines cross at a square corner (90°). @ 0:16
4. 90°. It is marked with a small square. @ 0:24
5. Perpendicular, because they make a square corner, even though they are turned. @ 0:41
6. The two tall sides of the H are parallel. The middle bar is perpendicular to each tall side. (Application question — not shown in the video)
Disclaimer: This worksheet was generated with AI assistance based on original video content. It is intended for educational reference only. Teachers are encouraged to review and adjust questions to fit their curriculum standards before classroom use.
🎯 Extension Activity: Have students write the capital letters A through L and use the corner of an index card to test each one. They mark parallel lines in blue, perpendicular lines in orange, and other intersecting lines in green, then share which letter has the most perpendicular lines.