VOLUME AND SURFACE AREA |Part-4| CUET L-30

Surface Areas and Volume

Surface area and volume are calculated for any three-dimensional geometrical shape. The surface area of any given object is the area or region occupied by the surface of the object. Whereas volume is the amount of space available in an object.

In geometry, there are different shapes and sizes such as sphere, cube, cuboid, cone, cylinder, etc. Each shape has its surface area as well as volume. But in the case of two-dimensional figures like square, circle, rectangle, triangle, etc., we can measure only the area covered by these figures and there is no volume available. Now, let us see the formulas of surface areas and volumes for different 3d-shapes.

What is Surface Area?

The space occupied by a two-dimensional flat surface is called the area. It is measured in square units. The area occupied by a three-dimensional object by its outer surface is called the surface area. It is also measured in square units.

Generally, Area can be of two types:

(i) Total Surface Area

(ii) Curved Surface Area/Lateral Surface Area

Total Surface Area

Total surface area refers to the area including the base(s) and the curved part. It is the total area covered by the surface of the object. If the shape has a curved surface and base, then the total area will be the sum of the two areas.

Curved Surface Area/Lateral Surface Area

Curved surface area refers to the area of only the curved part of the shape excluding its base(s). It is also referred to as lateral surface area for shapes such as a cylinder.

What is Volume?

The amount of space, measured in cubic units, that an object or substance occupies is called volume. Two-dimensional doesn’t have volume but has area only. For example, the Volume of the Circle cannot be found, though the Volume of the sphere can be. It is so because a sphere is a three-dimensional shape.

Learn more: Mathematics Grade 10

Surface Area and Volume Formulas

Below given is the table for calculating Surface area and Volume for the basic geometrical figures:

Name Perimeter Total Surface Area Curved Surface Area/Lateral Surface Area Volume Figure

Square 4b b2 —- —- Square

Rectangle 2(w+h) w.h —- —- Rectangle

Parallelogram 2(a+b) b.h —- —- Parallelogram

Trapezoid a+b+c+d 1/2(a+b).h —- —- Trapezoid

Circle 2 π r π r2 —- —- Circle

Ellipse 2π√(a2 + b2)/2       π a.b —- —- Ellipse

Triangle a+b+c 1/2 * b * h —- —- Triangle

Cuboid 4(l+b+h) 2(lb+bh+hl) 2h(l+b) l * b * h Cuboid

Cube 6a  6a2 4a2 a3 Cube

Cylinder —- 2 π r(r+h) 2πrh π r2 h Cylinder

Cone —- π r(r+l) π r l 1/3π r2 h Cone

Sphere —- 4 π r2 4π r2 4/3π r3 Sphere

Hemisphere —- 3 π r2 2 π r2 2/3π r3  Hemisphere