This key facts covers Perpendicular Lines within Parallel & Perpendicular for GCSE Mathematics. Revise Parallel & Perpendicular in Graphs for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 10 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 10
Practice
14 questions
Recall
12 flashcards
Perpendicular Lines
- Definition: Lines that meet at 90° (right angles)
- Key Property: Gradients multiply to give -1
- If one gradient is m, the other is -1/m
- Symbol: ⊥ (e.g., L₁ ⊥ L₂)
- Special case: Horizontal and vertical lines are always perpendicular
Keep building this topic
Read this section alongside the surrounding pages in Parallel & Perpendicular. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Parallel & Perpendicular
Which of the following is true about two parallel straight lines?
Explain why a horizontal line and a vertical line are always perpendicular to each other. Your explanation must refer to gradients.
Quick Recall Flashcards
14 questions on Parallel & Perpendicular — practise free
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