Class 8 Maths – Chapter 11

Mensuration

STEP 10: Full Revision + Exam Strategy

🔹 Quick Revision – Key Concepts

• Area is measured in square units (cm², m²).
• Volume is measured in cubic units (cm³, m³).
• Mensuration deals with measurement of area, surface area and volume.
• Cube, cuboid, cylinder and circle are important solids.

📐 Important Formula Chart

• Area of Rectangle = l × b
• Area of Square = a²
• Area of Circle = πr²
• Perimeter of Rectangle = 2(l + b)
• Volume of Cube = a³
• Volume of Cuboid = l × b × h
• Volume of Cylinder = πr²h

🧠 Easy Memory Tricks

• Cube: “One side → three times” → a³
• Circle: “Pie are square” → πr²
• Cylinder: “Circle × Height” → πr²h
• Cuboid: “Length–Breadth–Height multiply”

⚠️ Common Mistakes to Avoid

• Forgetting units in final answer.
• Using wrong formula for cube and cuboid.
• Not converting diameter into radius.
• Calculation errors in multiplication.

🧑‍🏫 Examiner’s Valuation View

• Correct formula = 1 mark
• Proper substitution = 1 mark
• Correct calculation = 1–2 marks
• Units = compulsory for full marks

✍️ How to Write Answers in Exam

1. Write the formula clearly.
2. Substitute given values.
3. Show calculations step-by-step.
4. Write final answer with unit.

🌟 Final Scoring Tip

Mensuration is a formula-based chapter. If formulas are clear and steps are shown neatly, full marks are guaranteed.