Grade 7

Grade 7Number System


Roots


Introduction to roots

In mathematics, the concept of "root" is foundational when dealing with numbers. Roots help us find a number that, when multiplied by a certain number of times, gives us the original number. The most common roots are square roots and cube roots. In this guide, we'll explore what roots are, how to find them, and how they work with different numbers.

What is the origin?

A "root" is a value that, when multiplied by itself a certain number of times, gives the original number. For example, finding a square root means finding a number that, when multiplied by itself once, gives you the initial number. Mathematically, the square root of a is written as √a.

For example, the square root of 9 is written like this:

√9 = 3

Because 3 multiplied by itself gives 9:

3 × 3 = 9

Square root

The most common type of root is the square root. It is called a "square" because it answers the question: "What number multiplied by itself gives that number?"

Example:

√16 = 4

4 × 4 = 16

To understand square roots, imagine a square. If the area of the square is a perfect square number, then the length of the side of the square is the square root of that number.

Length of side = √area 

Cube root

Another important root is the cube root. The cube root of a number is the value that when multiplied by itself twice gives the original number. The cube root is represented by .

For example, the cube root of 27 is:

∛27 = 3

Because:

3 × 3 × 3 = 27

Example:

∛64 = 4

4 × 4 × 4 = 64

Cube roots can be visualized by imagining a cube. The length of the side of a cube corresponds to the cube root of its volume.

Length of side = ∛volume 

Calculating the roots

Finding roots can be done in several ways. For common roots, such as square roots and cube roots of small perfect squares and cubes, you can often do the calculation in your head or use a mathematical approach.

Finding the square root

Consider the class of small numbers:

  • 1² = 1
  • 2² = 4
  • 3² = 9
  • 4² = 16

The originals will be:

  • √1 = 1
  • √4 = 2
  • √9 = 3
  • √16 = 4

Finding cube roots

Similarly, you can calculate the cube root of a number based on its cube:

  • 1³ = 1
  • 2³ = 8
  • 3³ = 27
  • 4³ = 64

The originals will be:

  • ∛1 = 1
  • ∛8 = 2
  • ∛27 = 3
  • ∛64 = 4

Applications of roots

Roots have practical applications in various fields such as architecture, engineering, and physics. Understanding roots can help solve problems involving quadratic equations, volume, area, and real-world projects that require accurate calculations.

Real life applications:

If you know that the volume of a cubic container is 125 cubic meters, you can find the length of its side by finding the cube root:

Side length = ∛125 = 5 m

Further exploration

Roots go beyond just square and cube roots. There are also fourth roots, fifth roots, and so on. The nth root of a number is the value that, when multiplied by itself n times, gives the original number.

Example of fourth root:

⁴√16 = 2

Because:

2 × 2 × 2 × 2 = 16

Practice:

Find the cube root of 125:

∛125 = 5

Conclusion

Understanding roots is an important part of mathematics. It allows you to explore deeper mathematical concepts and solve various problems more effectively. Whether you are dealing with simple geometry or complex algebra, mastering roots provides a solid foundation for learning.


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