Class 8 Maths - CBSE
Area
In the Class 8 CBSE chapter on Area, students learn to calculate the surface areas of various 2D and 3D geometric shapes. Building on previous knowledge of basic rectangles and triangles, this chapter introduces trapezium, general quadrilaterals, polygons, and the total and lateral surface areas of 3D solids like cubes, cuboids, and cylinders. Understanding this chapter is crucial as it forms the foundation for advanced mensuration in higher grades and regularly carries significant weight in school and board-related assessments.
Start Learning FreeKey Concepts
Area of a Trapezium
The area is calculated as half the product of the sum of the parallel sides and the perpendicular distance between them.
Area of a General Quadrilateral
A quadrilateral can be split into two triangles by drawing a diagonal, allowing the total area to be found by summing the areas of both triangles.
Area of Polygons
Complex polygons are divided into simpler shapes like triangles and trapeziums so that individual areas can be calculated and added together.
Surface Area of Cuboid and Cube
Total surface area is the sum of the areas of all flat faces enclosing the 3D solid, measured in square units.
Surface Area of a Cylinder
It includes the curved surface area plus the area of the two circular flat bases at the top and bottom.
Important Formulas
Board Exam Info
In CBSE Class 8 Mathematics, Mensuration and Area-related chapters typically carry around 6 to 8 marks in the final exams. Questions generally include direct formula applications, word problems involving field measurements, and multi-step problems where composite shapes must be split into simpler figures.
Frequently Asked Questions
Curved surface area only includes the outer wrapping area excluding the top and bottom bases, whereas total surface area includes the curved part plus the areas of the top and bottom bases.
Curved surface area only includes the outer walls or wrapping area excluding the top and bottom bases, whereas total surface area includes the curved part plus the areas of the top and bottom bases.
How do I find the area of an irregular polygon?
You divide the irregular polygon into standard non-overlapping shapes like triangles, rectangles, or trapeziums, calculate their individual areas, and add them all together.
Why is the unit of area always squared?
Area measures a two-dimensional space by multiplying two length dimensions together (such as length times breadth), resulting in units like square centimeters (cm^2) or square meters (m^2).
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