Example 1
The perimeter of a rectangle is 100 m and its length is 26 m. What is its area?
Answer: C) 624 m²
Breadth = 100/2 − 26 = 24 m; area = 26 × 24 = 624 m².
Mensuration questions for competitive exams: rules, worked examples and practice
Mensuration covers the perimeter, area and volume of 2D and 3D shapes. Most questions apply one formula after finding a missing length.
Key rules and formulas
- Rectangle: perimeter = 2(l + b), area = l × b.
- Circle: circumference = 2πr, area = πr².
- Cylinder: volume = πr²h, curved surface area = 2πrh.
- Cube: volume = a³, surface area = 6a²; cuboid volume = l × b × h.
Common traps
- Using the diameter where the formula needs the radius.
- Mixing units (cm with m) before multiplying.
Where Mensuration is asked
- RRB Group D (Mathematics)
- RRB NTPC CBT 1 (Mathematics)
- SSC CGL Tier 1 (Quantitative Aptitude)
- SSC CGL Tier 2 (Mathematical Abilities)
- SSC CHSL Tier 1 (Quantitative Aptitude)
Worked examples
Example 2
Find the volume of a cylinder with radius 14 cm and height 17 cm. (π = 22/7)
Answer: D) 10,472 cm³
V = πr²h = 22/7 × 14² × 17 = 10,472 cm³.
Example 3
What is the area of a circle of radius 28 cm? (Take π = 22/7)
Answer: B) 2,464 cm²
Area = πr² = 22/7 × 28 × 28 = 2,464 cm².
More Mensuration practice questions
- The perimeter of a rectangle is 48 m and its length is 14 m. What is its area?
- Find the volume of a cylinder with radius 7 cm and height 12 cm. (π = 22/7)
- The perimeter of a rectangle is 82 m and its length is 27 m. What is its area?
- Find the volume of a cylinder with radius 7 cm and height 14 cm. (π = 22/7)
- What is the area of a circle of radius 14 cm? (Take π = 22/7)
Frequently asked questions
What is Mensuration in competitive exams?
Mensuration covers the perimeter, area and volume of 2D and 3D shapes. Most questions apply one formula after finding a missing length.
Which exams ask Mensuration questions?
On MockBazaar, Mensuration questions appear in RRB Group D, RRB NTPC CBT 1, SSC CGL Tier 1, SSC CGL Tier 2, SSC CHSL Tier 1.
What is the most common mistake in Mensuration?
Using the diameter where the formula needs the radius.