Lines and Angles • Topic 1 of 3

Types of Lines

In geometry, a line is a straight path. In Grade 4, we study three important relationships between lines:

  • Parallel Lines: Lines that never meet and are always the same distance apart. Like railway tracks or opposite edges of a ruler.
  • Perpendicular Lines: Lines that meet at exactly 90 degrees (a right angle). Like the corner of a room or the letter L.
  • Intersecting Lines: Lines that cross each other at any angle. Like scissors or roads crossing at a junction.

A line segment has two endpoints. A ray has one endpoint and goes on forever in one direction.

Types of LinesParallelNever meetPerpendicularMeet at 90 degreesIntersectingCross at any angle
Solved Examples
1
Worked Example
Identify the type of lines formed by the two vertical bars in the letter 'H'.
SolutionThe two vertical lines in 'H' are parallel — they run in the same direction, are always the same distance apart, and never meet.
2
Worked Example
Give two real-life examples each of parallel and perpendicular lines.
SolutionParallel: railway tracks, opposite edges of a notebook. Perpendicular: corner of a wall meets the floor at 90 degrees; the letter 'L' shows perpendicular lines.
3
Worked Example
A road runs north-south. Another road crosses it going east-west. What type of lines do they form?
SolutionThey form intersecting lines. If the crossing is at exactly 90 degrees, they are also perpendicular lines.

Key Points

  • Parallel lines: never meet, always same distance apart (like train tracks)
  • Perpendicular lines: meet at exactly 90 degrees (right angle)
  • Intersecting lines: cross each other at any angle
  • A line segment has two endpoints; a ray has one endpoint and goes on forever
Quick Check — 4 MCQs
Tap an option to check your answer0 / 4
Q1.Lines that never meet are:
Explanation: Parallel.
Q2.Lines that meet at a right angle are:
Explanation: Perpendicular ($90^\circ$).
Q3.Lines that cross at a point are:
Explanation: Intersecting.
Q4.A line segment has how many endpoints?
Explanation: Two.
Practice more MCQs → 📝 Assignment · 35 marks