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Parallel lines
Two distinct lines in the same plane are parallel if they never meet, even when extended. The shortest distance between them stays the same. They can be drawn horizontally, vertically, or diagonally.
Intersecting lines
When two distinct lines in a plane share a point, they intersect. That point is their intersection. Two short drawn lines that do not touch are not necessarily parallel. Imagine extending them.
Perpendicular lines
Perpendicular lines meet at a right angle of 90°. They are a special case of intersecting lines. A small square in a drawing marks a right angle.
Try it yourself
On a rectangular notebook, find two opposite edges and two adjacent edges. Which represent parallel directions, and which represent perpendicular directions?
See an example answer
Opposite edges represent parallel directions. Adjacent edges meet at a right angle and represent perpendicular directions.
Check your knowledge
Choose one answer for each question. You can revise your answers and check again.
Answer key
- Never intersect. They do not meet even when extended.
- 90°. A right angle measures 90°.
- Yes. Their position on the paper does not determine whether they are parallel.
- The intersection. The intersection is the point the lines share.
- No, the angle must be 90°. Not all intersecting lines are perpendicular.