MH Police Bharti · Bite-size lessons
Mensuration
About 6 min · Mathematics · English
Time worked out from the lesson's 356 words at 150 words a minute, plus a minute for each question.
Mensuration is one of the most formula-intensive topics in the Maharashtra Police Bharti Mathematics section. It deals with the measurement of geometric shapes—calculating perimeter, area for 2-D figures and surface area, volume for 3-D figures. Questions may involve direct formula application or multi-step problems combining two or more shapes.
Key ideas
- Perimeter is the total length of the boundary of a 2-D shape. Think of it as the length of fencing needed to enclose a plot.
- Area is the surface enclosed within the boundary of a 2-D figure. It tells you how much paint or carpet is needed.
- Surface Area of a 3-D object is the total area of all its outer faces—relevant for painting, wrapping, or coating problems.
- Volume measures the space inside a 3-D object. It answers "how much water/sand/air can this container hold?"
- Lateral/Curved Surface Area (LSA/CSA) excludes the top and bottom faces—used when only the sides are painted or wrapped.
Watch out for
- Confusing radius with diameter → Always check if the problem gives diameter; divide by 2 to get radius before applying formulas.
- Mixing up LSA and TSA → Read carefully: "curved surface" or "sides only" means LSA; "total surface" or "all faces" means TSA.
- Ignoring unit conversion → If length is in metres and you need area in cm², first convert all dimensions to cm, then calculate.
Quick reference
- Square: Area = a², Perimeter = 4a
- Rectangle: Area = lb, Perimeter = 2(l+b)
- Circle: Area = πr², Circumference = 2πr
- Cube: Volume = a³, TSA = 6a²
- Cylinder: Volume = πr²h, CSA = 2πrh
Check yourself: 3 questions
1. A rectangular plot measures 40 metres in length and 25 metres in breadth. What is the perimeter of the plot?
2. A square field has a side of 50 metres. A farmer wants to fence the field with wire. If the cost of fencing is Rs. 15 per metre, what is the total cost of fencing?
3. A circular park has a radius of 21 metres. What is the area of the park? (Take pi = 22/7)
This lesson is cut from the topic's note, not rewritten. Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.
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