What Is Mensuration Class 8 Science: Definition & Key Concepts
By ConceptScroll Team · Published on 19 June 2026 · 4 min read
What is mensuration class 8 science? Mensuration is the branch of mathematics that deals with measuring lengths, areas, and volumes of different geometric shapes and solids. In Class 8 NCERT, this chapter helps students understand formulas and applications to solve real-life problems related to measurement.
Introduction to Mensuration in Class 8 Science
Mensuration is a crucial chapter in Class 8 NCERT Mathematics. It focuses on measuring lengths, areas, and volumes of various two-dimensional (2D) and three-dimensional (3D) shapes. This branch helps students apply mathematical concepts to real-world problems like finding the surface area of boxes or the volume of water in containers.
Key points:
- Measures length, area, and volume
- Applies to both flat shapes and solids
- Uses formulas for calculation
Understanding mensuration builds a strong foundation for higher classes and competitive exams.
Basic Concepts and Definitions in Mensuration
Before diving into formulas, it's important to understand these basic terms:
- Length: The measurement of something from end to end.
- Area: The amount of space inside a 2D shape, measured in square units (e.g., $cm^2$, $m^2$).
- Volume: The amount of space a 3D object occupies, measured in cubic units (e.g., $cm^3$, $m^3$).
- Surface Area: The total area of all the faces or surfaces of a 3D shape.
These definitions help in solving mensuration problems accurately.
Want to test yourself on Mensuration? Try our free quiz →
Common Formulas for 2D Shapes in Class 8 Mensuration
Class 8 NCERT covers several important 2D shapes. Here are their key area formulas:
| Shape | Formula for Area |
|---|---|
| Square | $A = a^2$ (where $a$ is side) |
| Rectangle | $A = l \times b$ (length × breadth) |
| Triangle | $A = \frac{1}{2} \times base \times height$ |
| Parallelogram | $A = base \times height$ |
| Circle | $A = \pi r^2$ (where $r$ is radius) |
Example: Find the area of a rectangle with length 8 cm and breadth 5 cm.
$$ A = l \times b = 8 \times 5 = 40\, cm^2 $$
Surface Area and Volume of 3D Solids
Mensuration also includes calculating surface area and volume of solids such as cubes, cuboids, cylinders, cones, and spheres.
Key formulas:
- Cube:
- Surface Area = $6a^2$
- Volume = $a^3$
- Cuboid:
- Surface Area = $2(lb + bh + hl)$
- Volume = $l \times b \times h$
- Cylinder:
- Surface Area = $2\pi r(h + r)$
- Volume = $\pi r^2 h$
- Cone:
- Surface Area = $\pi r(l + r)$ (where $l$ is slant height)
- Volume = $\frac{1}{3} \pi r^2 h$
- Sphere:
- Surface Area = $4\pi r^2$
- Volume = $\frac{4}{3} \pi r^3$
Example: Calculate the volume of a cylinder with radius 7 cm and height 10 cm.
$$ V = \pi r^2 h = \pi \times 7^2 \times 10 = 490\pi \approx 1538.4\, cm^3 $$
Tips for Mastering Mensuration in Class 8 NCERT
To excel in mensuration:
- Understand each formula and when to use it.
- Practice solved examples from the NCERT textbook.
- Draw diagrams to visualize problems.
- Memorize units and convert them carefully.
- Attempt all exercises at the end of the chapter.
- Review mistakes and clarify doubts promptly.
Regular practice will build confidence and improve problem-solving speed.
Comparison of Area and Volume Units
Understanding units is vital in mensuration. Here's a quick comparison:
| Measurement | Unit Example | Relation to Base Unit |
|---|---|---|
| Length | 1 m | Base unit for length |
| Area | 1 $m^2$ | $1 m^2 = 1 m \times 1 m$ |
| Volume | 1 $m^3$ | $1 m^3 = 1 m \times 1 m \times 1 m$ |
Always convert units to the same system before calculating. For example, convert cm to m if needed.
Frequently asked questions
What is mensuration in Class 8 science?
Mensuration is the study of measuring lengths, areas, and volumes of geometric shapes and solids.
Which formulas are important in Class 8 mensuration?
Formulas for area of 2D shapes and surface area and volume of 3D solids are key.
How do I calculate the volume of a cylinder?
Use the formula $V = \pi r^2 h$, where $r$ is radius and $h$ is height.
Why is mensuration important for Class 8 exams?
It helps solve real-life measurement problems and is a major part of the NCERT syllabus.
What units are used in mensuration?
Length in meters or centimeters, area in square units, and volume in cubic units.
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