Course Content
Chapter 01 – Sets
A set is a group of elements in brackets that are related to one another. In this chapter, you will learn about the differences and similarities between an equal set and an equivalent set, and describe the notion and types of sets.
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Chapter 02 – Whole Numbers
Numbers are everywhere in our world. In this chapter, we'll learn about whole numbers, and will explore what a whole number is and how we use these types of numbers in our everyday lives.
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Chapter 03 – Factors and Multiples
Multiples and factors are basic mathematical concepts. Review these terms and how they are applied to real-world scenarios, and practice applying them to solve sample word problems. Learning how to divide can be a little challenging, but knowing some basic rules about dividing can help. In this chapter, you'll learn about the divisibility rules that apply to numbers.
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Chapter 04 – Integers
An integer is a whole number (not a fractional number) that can be positive, negative, or zero. In this chapter, we'll learn about mathematical operations with integers using the operations of addition, subtraction, multiplication, and division. Discover the properties of integers and how those properties affect the solution to different types of math problems.
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Chapter 05 – Simplification
Simplifying math expression is an important part of helping students learn how to work and think algebraically. The order of operations in mathematics is the sequence in which a problem is solved. In this chapter, we'll explore the definition and examples of the order of operations in math, discover the steps involved, and learn the shortcut for remembering the steps defined by the acronym BODMAS and PEMDAS.
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Chapter 06 – Ratio and Proportions
Ratios allow us a way to mathematically compare two or more items, and proportions can help us find out even more information. In this chapter, we'll learn the definition of ratios and proportions, and understand how to calculate the ratio and proportion problems.
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Chapter 07 – Financial Arithmetic
Many values we come across regularly change frequently. In this chapter, we will look at examples when a quantity decreases in value, and how such decreases can be represented using percentages. A company may have a great product but if they are losing money, it will eventually go out of business. We will explore profit and loss from an economic perspective.
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Chapter 08 – Introduction to Algebra
To evaluate simple algebraic expressions, substitute a number for each variable and solve. In this chapter, we'll learn the steps for evaluating simple algebraic expressions, including rules for order of operations and parentheses, and tackle the practice problems.
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Chapter 09 – Linear Equations
A system of linear equations refers to a set of linear equations that have similar variables. In this chapter, we'll explore the definition and examples of a system of linear equations, and learn how to find the solution to a system of linear equations.
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Chapter 10 – Geometry
Geometry is a sector of mathematics that analyzes shapes, lines, and surfaces. It is possible to construct different geometric shapes and patterns using lines and angles. In this chapter, we'll explore the definition of the basics of geometry: points, lines, and angles, geometric construction, the tools required for the job, and how to copy angles and line segments.
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Chapter 11 – Perimeter and Area
A perimeter is a measurement used to determine the distance of a path around the outer edge of a two-dimensional object. In this chapter, we'll discover the formula to calculate perimeter for various shapes and consider the usefulness of these equations through examples. Discover how to find the area of an irregular polygon. Explore formulas for the area of regular polygons, learn how to divide an irregular polygon into a series of regular polygons, and see how to find the area using those pieces.
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Chapter 12 – Three Dimensional Shapes
Geometric measurements can be taken for one-, two-, and three-dimensional shapes. In this chapter, we'll explore the most common formulas one would use to find the perimeter, area, surface area, and volume of three-dimensional figures.
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Chapter 13 – Information Handling
Data handling refers to the process of gathering, recording, and presenting information in a way that is helpful to others - for instance, in graphs or charts.
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Grade 6 – Mathematics
About Lesson

Cube and cuboid are three-dimensional shapes that consist of six faces, eight vertices, and twelve edges. The primary difference between them is a cube has all its sides equal whereas the length, width, and height of a cuboid are different. Both shapes look almost the same but have different properties.

Cube: 

A cube is a three-dimensional shape that is defined in the XYZ plane. It has six faces, eight vertices, and twelve edges. All the faces of the cube are square in shape and have equal dimensions.

 

Cuboid: 

A cuboid is also a polyhedron having six faces, eight vertices, and twelve edges. The faces of the cuboid are parallel. However, not all the faces of a cuboid are equal in dimensions.

Hence, cube and cuboid shapes have six faces, eight vertices, and twelve edges.

 

Difference Between Cube and Cuboid:

The differences between the cube and cuboid shapes are as follows:

  • The sides of the cube are equal but for cuboids they are different.
  • The sides of the cube are square, but the cuboids are in rectangular shape.
  • All the diagonals of the cube are equal but a cuboid has equal diagonals for only parallel sides.

 

Cube and Cuboid Shape:

As we already know, both cube and cuboid are in 3D shape, whose axes go along the x-axis, y-axis and z-axis. Now, let us learn in detail.

A cuboid is a closed 3-dimensional geometrical figure bounded by six rectangular plane regions.

Volume and Surface Area of Cuboid | Lateral Surface Area of a Cuboid

 

Properties of a Cuboid:

Below are the properties of the cuboid, its faces, base and lateral faces, edges, and vertices.

  • Faces of Cuboid

A Cuboid is made up of six rectangles, each of the rectangles is called the face. In the figure above, ABFE, DAEH, DCGH, CBFG, ABCD, and EFGH are the 6 faces of the cuboid.

The top face ABCD and the bottom face EFGH form a pair of opposite faces. Similarly, ABFE, DCGH, and DAEH, CBFG are pairs of opposite faces. Any two faces other than the opposite faces are called adjacent faces.

 

Consider a face ABCD, the adjacent faces to this are ABFE, BCGF, CDHG, and ADHE.

  • Base and lateral faces

Any face of a cuboid may be called the base of the cuboid. The four faces which are adjacent to the base are called the lateral faces of the cuboid. Usually, the surface on which a solid rests is known to be the base of the solid.

In Figure (1) above, EFGH represents the base of a cuboid.

 

  • Edges

The edge of the cuboid is a line segment between any two adjacent vertices.

There are 12 edges, they are AB, AD, AE, HD, HE, HG, GF, GC, FE, FB, EF, and CD and the opposite sides of a rectangle are equal.

Hence, AB = CD = GH = EF, AE = DH = BF = CG and EH = FG = AD = BC.

 

  • Vertices

The point of intersection of the 3 edges of a cuboid is called the vertex of a cuboid.

A cuboid has 8 vertices. A, B, C, D, E, F, G and H represent vertices of the cuboid in fig 1.

By observation, the twelve edges of a cuboid can be grouped into three groups, such that all edges in one group are equal in length, so there are three distinct groups and the groups are named as length, breadth, and height.

 

A solid having its length, breadth, and height all to be equal in measurement is called a cube. A cube is a solid bounded by six square plane regions, where the side of the cube is called the edge.

 

Properties of Cube:

  • A cube has six faces and twelve edges of equal length.
  • It has square-shaped faces.
  • The angles of the cube in the plane are at a right angle.
  • Each face of the cube meets four other faces.
  • Each vertex of the cube meets three faces and three edges.
  • The opposite edges of the cube are parallel to each other.

 

Cube and Cuboid Formulas:

The formulas for cube and cuboid shapes are defined based on their surface areas, lateral surface areas, and volume.

Cube  Cuboid
Total Surface Area = 6(side)2 Total Surface area = 2 (length × breadth + breadth × height + length × height)
Lateral Surface Area = 4 (Side)2 Lateral Surface area = 2 height(length + breadth)
Volume of cube = (Side)3 Volume of the cuboid = (length × breadth × height)
Diagonal of a cube = √3(side) Diagonal of the cuboid =√( length2 + breadth2 +height2)
Perimeter of cube = 12 × side Perimeter of cuboid = 4 (length + breadth + height)

 

Surface Area of Cube and Cuboid

The surface area of a cuboid is equal to the sum of the areas of its six rectangular faces.

Volume and Surface Area of Cuboid | Lateral Surface Area of a Cuboid

Consider a cuboid having the length to be ‘l’ cm, breadth be ‘b’ cm and height be ‘h’ cm.

  • Area of face EFGH = Area of Face ABCD = (l × b) cm2
  • Area of face BFGC = Area of face AEHD = (b × h) cm2
  • Area of face DHGC = Area of face ABFE = (l × h) cm2

Total surface area of a cuboid = Sum of the areas of all its 6 rectangular faces

Total Surface Area of Cuboid= 2 (lb + bh +lh)

 

Example: If the length, breadth, and height of a cuboid are 5 cm, 3 cm, and 4 cm, then find its total surface area.

Given, Length, l = 5 cm, Breadth, b = 3 cm, and Height, h = 4 cm.

Total surface area (TSA) = 2(lb + bh + lh)

= 2(5 × 3 + 3 × 4 + 5 × 4)

= 2(15 + 12 + 20)

= 2(47)

= 94 sq.cm.

 

Lateral surface area of a Cuboid:

The sum of surface areas of all faces except the top and bottom face of a solid is defined as the lateral surface area of a solid.

Consider a Cuboid of length, breadth, and height to be l, b, and h respectively.

Lateral surface area of the cuboid= Area of face ADHE + Area of face BCGF + Area of face ABFE + Area of face DCGH

=2(b × h) + 2(l × h)

=2h(l + b)

LSA of Cuboid = 2h(l +b)

 

Example: If the length, breadth and height of a cuboid are 5 cm, 3 cm and 4 cm, then find its lateral surface area.

Given, Length = 5 cm, Breadth = 3 cm and Height = 4 cm

LSA = 2h(l + b)

LSA = 2 × 4(5 + 3)

LSA = 2 × 4(8)

LSA = 2 × 32 = 64 cm2

 

Surface Area of a Cube

For cube, length = breadth = height

Suppose the length of an edge = l

Hence, surface area of the cube = 2(l × l +l × l + l × l) = 2 x 3l = 6l2

Total Surface Area of Cube= 6l2

 

Example: If the length of the side of the cube is 6 cm, then find its total surface area.

Given, side length = 6 cm

TSA of cube = 6l2

 TSA = 6 (6)2

TSA = 6 × 36

TSA = 216 sq.cm

 

Lateral surface area of a Cube:

Formula to find the Lateral surface area of the cube is:
2(l × l + l × l) = 4l2

LSA of Cube = 4l2

 

Example: If the length of the side of the cube is 6 cm, then find its lateral surface area.

Given,

Side length, l = 6 cm

LSA of cube = 4l2 

LSA = 4 (6)2

LSA = 4 x 36 = 144 sq.cm

 

Volume of the Cube and Cuboid

Volume of Cuboid:

The volume of the cuboid is equal to the product of the area of one surface and height.

Volume of the cuboid = (length × breadth × height) cubic units

Volume of the cuboid = ( l × b × h) cubic units

 

Example: If the length, breadth and height of a cuboid are 5 cm, 3 cm and 4 cm, then find its volume.

Given, Length (l) = 5 cm, Breadth (b) = 3 cm and Height (h) = 4 cm

Volume of cuboid = l × b × h

V = 5 × 3 × 4

V = 60 cubic cm

 

Volume of the Cube:

The volume of the cube is equal to the product of the area of the base of a cube and its height. As we know already, all the edges of the cube are of the same length. Hence,

Volume of the cube = l2 × h

Since, l = h

Therefore,

Volume of the cube = l2 × l

Volume of the cube = lcubic units

 

Example: If the length of the side of the cube is 6 cm, then find its volume.

Given, side length = 6 cm

Volume of cube = side3 

V = 63

V = 216 cubic cm

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