Knowledge Organiser: Area of Parallelograms & Trapeziums
Part of Area of Parallelograms & Trapeziums · GCSE GCSE Mathematics revision
This topic summary covers Knowledge Organiser: Area of Parallelograms & Trapeziums within Area of Parallelograms & Trapeziums for GCSE Mathematics. Revise Area of Parallelograms & Trapeziums in Geometry & Measures for GCSE Mathematics with 11 exam-style questions and 4 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 8 of 8 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 8
Practice
11 questions
Recall
4 flashcards
Knowledge Organiser: Area of Parallelograms & Trapeziums
Key Terms
- Parallelogram: Quadrilateral with two pairs of parallel sides
- Trapezium: Quadrilateral with exactly one pair of parallel sides
- Perpendicular height: The vertical height at 90° to the base (NOT the slant side)
- Parallel sides: The two sides labelled a and b in the trapezium formula
Must-Know Facts
- Parallelogram area = base × perpendicular height (same as rectangle)
- Trapezium: add the parallel sides first, then multiply by height, then halve
- Height is ALWAYS perpendicular (90°) — never use the slanted side
- Trapezium formula works because it finds the average width times height
- Area is always in square units: cm², m²
Key Formulas
- Parallelogram: A = b × h
- Trapezium: A = ½ × (a + b) × h
- Reverse (find height): h = A ÷ b
Common Mistakes
- Parallelogram — using slant height: Must use the perpendicular height, not the slant side
- Trapezium — wrong bases: a and b are the two PARALLEL sides — identify these carefully from the diagram
- Forgetting the ½ in trapezium: A = ½(a + b)h — the ½ is always required
- Units: Area answers must be in square units (cm², m²) — never linear units
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Practice Questions for Area of Parallelograms & Trapeziums
A parallelogram has base b and perpendicular height h. Which formula gives its area?
Explain why the area formula for a parallelogram is the same as the area formula for a rectangle.
Quick Recall Flashcards
11 questions on Area of Parallelograms & Trapeziums — practise free
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