Class 9 Maths Surface Areas Volumes Introduction


Area is the amount of space inside a boundary of a 2D object.

Surface area of a solid 3D object is the measure of the total area that a surface of an object occupies. It is measured in m2, cm2 etc

We generally talk about inner surface area & outer surface area.

Surface area is typically used to determine cost of painting for a given 3D object.

Volume is the quantity of 3D space enclosed by some closed boundary. It is measured in m3, cm3, ltr etc.

It is typically used to determine quantity of liquid, air, grains etc in a 3D container.


We will study Surface Area & Volume for Cube, Cuboid, Sphere, Cone and Cylinder.

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