5.6 - Square Roots of Decimals

Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Introduction to Square Roots of Decimals

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

Teacher
Teacher

Today, we’re going to learn how to find the square roots of decimal numbers, starting with basic definitions. Can anyone tell me what a square root is?

Student 1
Student 1

A square root of a number is a value that, when multiplied by itself, gives the original number.

Teacher
Teacher

Exactly! For example, the square root of 16 is 4 because 4 times 4 equals 16. Now, what about decimal square roots? How might they differ?

Student 2
Student 2

I guess they also have to be multiplied by themselves, right?

Teacher
Teacher

Absolutely, and that's where it can get tricky. Let’s look at an example—17.64.

Finding the Square Root of a Decimal

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

Teacher
Teacher

To find the square root of 17.64, we start placing bars on 17 and then on every pair after the decimal. Who can help me illustrate this?

Student 3
Student 3

We can put bars on 17 and on 64, like this. |17|.|64|.

Teacher
Teacher

Great! Now we estimate the divisor based on the first bar, correct?

Student 4
Student 4

Yes! Since 42 is less than 17 and 52 is more, we use 4 as the divisor.

Teacher
Teacher

Right! Let's divide and find the remainder now. What do we get?

Student 1
Student 1

The remainder is 1, and we bring down the 64 next!

Teacher
Teacher

Yes, now we have 164. Let’s continue with doubling the divisor.

Continuing with Decimal Square Roots

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

Teacher
Teacher

Now, what happens when we double our divisor, which is 4?

Student 2
Student 2

The new divisor will be 8 with a blank on its right!

Teacher
Teacher

Exactly! If we know that 82 times 2 makes 164, what’s our new digit?

Student 3
Student 3

It’s 2!

Teacher
Teacher

Wonderful! And once our remainder is 0, what can we conclude?

Student 4
Student 4

That the square root of 17.64 is 4.2!

Finding Square Roots of Other Decimals

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

Teacher
Teacher

Now, let's practice finding square roots of other decimal numbers like 2.56 and 7.29. Who can show us how to start?

Student 1
Student 1

We place bars on 2 and on 56 for 2.56.

Teacher
Teacher

Correct! What would the steps be after that?

Student 2
Student 2

We find the divisor and divide it!

Teacher
Teacher

Exactly! Keep practicing with different decimal numbers at home.

Real-Life Applications

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

Teacher
Teacher

Let’s discuss how square roots are used in real life. Can anyone share an example?

Student 4
Student 4

I think in architecture! Like measuring the sides of a square area!

Teacher
Teacher

Absolutely! For example, if we know the area of a square plot is 2304 m², how would we find the side length?

Student 3
Student 3

We’d take the square root of 2304!

Teacher
Teacher

Perfect! And that would give us the side length of 48 m.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

This section covers the calculation of square roots of decimal numbers using the division method.

Standard

In this section, we explore the process of finding the square roots of decimals, emphasizing the division method and offering examples to illustrate each step. It also compares the placement of bars on integral and decimal parts of numbers.

Detailed

Square Roots of Decimals

In this section, we focus on the methods used to find the square roots of decimal numbers, primarily through the division method, which is structured and systematic. We begin with a concrete example, taking 17.64, and outline the steps:

  1. Placing Bars: Begin by placing bars over the integral part and every pair of digits in the decimal part. For 17.64, bars are placed over 17 and over 64 as 0.64.
  2. Finding Divisors: Use the leftmost bar to establish the range for the divisor, determining an approximate value.
  3. Working with Remainders: After performing the division, the remainder assists in bringing down digits in the subsequent steps, continually refining our divisor estimates.
  4. Completion: When the remainder completes the process without additional bars left, the square root can then be simplified to its decimal value.

Following this, we examine complex square roots of numbers like 176.341 and 2304 m², honing in on the practical applications of calculating square roots in real-life scenarios, such as determining the side of a square plot from its area. Finally, the section includes diverse exercises to practice and understand the concepts further.

Youtube Videos

Square roots of Decimals : Division Method | Class 8 | CBSE | NCERT | ICSE
Square roots of Decimals : Division Method | Class 8 | CBSE | NCERT | ICSE
Square roots of decimal numbers | Square root of decimals |
Square roots of decimal numbers | Square root of decimals |
Class 8 CBSE Maths | Squares & Square Roots - Square Root of Decimals | Xylem Class 8 CBSE
Class 8 CBSE Maths | Squares & Square Roots - Square Root of Decimals | Xylem Class 8 CBSE
Finding Square root of a decimal number - More than million views
Finding Square root of a decimal number - More than million views
Square Roots of Decimals - Square and Square Roots | Class 8 Maths
Square Roots of Decimals - Square and Square Roots | Class 8 Maths
Square Roots of Decimals - Squares and Square Roots | Class 8 Maths Ch 5 | CBSE 2024-25
Square Roots of Decimals - Squares and Square Roots | Class 8 Maths Ch 5 | CBSE 2024-25
Do you remember the square roots of these perfect squares? 🤯 #Shorts #math #maths #mathematics
Do you remember the square roots of these perfect squares? 🤯 #Shorts #math #maths #mathematics
Square and Square Roots in One Shot | Maths - Class 8th | Umang | Physics Wallah
Square and Square Roots in One Shot | Maths - Class 8th | Umang | Physics Wallah
Squares and Square Roots || 8 Min || CBSE Class 8 Math Rapid Revision || Ayush Sir
Squares and Square Roots || 8 Min || CBSE Class 8 Math Rapid Revision || Ayush Sir
Cube Root Math Trick
Cube Root Math Trick

Audio Book

Dive deep into the subject with an immersive audiobook experience.

Finding Square Roots of Decimal Numbers

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Consider 17.64
Step 1 To find the square root of a decimal number we put bars on the integral part (i.e., 17) of the number in the usual manner. And place bars on the decimal part (i.e., 64) on every pair of digits beginning with the first decimal place. Proceed 17.64.

Step 2 Now proceed in a similar manner. The left most bar is on 17 and 42 < 17 < 52. Take this number as the divisor and the number under the left-most bar as the dividend, i.e., 17. Divide and get the remainder.

Detailed Explanation

To find the square root of a decimal number like 17.64, we need to first separate the integral and decimal parts. For the integral part (17), we place a bar over it as we would do for whole numbers. For the decimal part (64), we create bars for each pair starting from the decimal point (e.g., 64 forms one pair). Next, we determine a digit that, when multiplied with itself, gives us a value less than or equal to the integral part. In this case, it will be 4, since 4 squared (16) is the largest perfect square less than 17.

Examples & Analogies

Imagine a garden that is shaped like a square. If the area of the garden is 17.64 square meters, you want to figure out how long each side of the garden is. By understanding that the side length must be a decimal number, you can see that finding the square root is like measuring how much space you need for each side to keep your garden a perfect square!

Step-by-Step Example of Finding a Square Root

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Step 3 The remainder is 1. Write the number under the next bar (i.e., 64) to the right of this remainder, to get 164.

Step 4 Double the divisor and enter it with a blank on its right.

Step 5 We know 82 × 2 = 164, therefore, the new digit is 2. Divide and get the remainder.

Step 6 Since the remainder is 0 and no bar left, therefore 17.64 = 4.2.

Detailed Explanation

Continuing with our example, after we found the first quotient part (4), we then look for the next decimal. We combine our dividend (the previous remainder) with the next pair of digits, which forms 164 when we add the next bar. By doubling our previous divisor (4) we prepare for the next calculation to find the second digit of the square root. Here, 82 times 2 equals to 164, which confirms that ‘2’ is a new digit, giving us a total square root of 4.2 for our number.

Examples & Analogies

Think of baking a cake. Just like each layer of the cake has to fit perfectly to make the entire cake look good, each step in finding the square root also has to fit perfectly into the overall calculation, ensuring that the final answer is both correct and neat, just like your nicely layered cake!

Example of Finding Another Square Root of a Decimal

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Example 13: Find the square root of 12.25.
Solution: Therefore, 12.25 = 3.5.

Detailed Explanation

In this example, we start with the number 12.25. Following similar steps as before, we identify the integral part (12) and the decimal part (25). We calculate the square root in a similar fashion. The process reveals that the square root amounts to 3.5, which indicates the side length of a square plot that would equal 12.25 square meters in area.

Examples & Analogies

Imagine a floor tile that is square. If the total area that the tile covers is 12.25 square feet, finding the side length (3.5 feet) is crucial to know how many such tiles you need. Each time you measure for tiles, it’s like those steps we took to measure for the square root!

Understanding Decimal Conversion in Square Roots

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Consider a number 176.341. Put bars on both integral part and decimal part. In what way is putting bars on decimal part different from integral part?

Detailed Explanation

When working with decimal numbers like 176.341, we visualize the square root process by using bars to group digits. For the integral part, we start from the unit’s place and move leftward. For the decimal part, we start from the decimal point and move rightward. This understanding is essential as it affects our calculations and the placement of decimal points in our final result.

Examples & Analogies

Think about reading a book. Just as you start from the first page and read to the back, you also need to start with the decimal from its point and move forward. This process helps you keep track of where you are, just like putting bars in our decimal calculations keeps our steps organized.

Applying Square Roots in Real Situations

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Example 14: Area of a square plot is 2304 m2. Find the side of the square plot.
Solution: Therefore, side of the square plot = 2304m.

Detailed Explanation

In this situation, for a square plot with an area of 2304 square meters, we need to find the side length. Just like calculating other roots, the square root tells us the length of one side. We find that the square root of 2304 is 48 meters, meaning if you wanted to fence the plot, each side of your fence would measure 48 meters.

Examples & Analogies

Imagine you are planning a square garden. If you know the area you want to cover is 2304 square meters, finding the sides is equivalent to knowing the length of each colorful row of flowers you will plant, keeping the garden beautifully symmetric!

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • Division Method: A step-by-step approach to determine the square root of decimals and integers by systematic division and estimating divisors.

  • Bar Placement: The technique of placing bars over the integral and decimal parts to facilitate finding square roots.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • To find the square root of 17.64 using the division method: Place bars on 17 and 64, estimate the divisor, then divide and find the square.

  • For the area of a square plot 2304 m², the side lengths can be calculated by finding the square root, leading to 48 m.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • To find the roots of decimals, let’s take our time, Step by step, in rhythm and rhyme.

📖 Fascinating Stories

  • Imagine finding treasure, with coordinates like numbers, use square roots to uncover them, a mathematical wonder!

🧠 Other Memory Gems

  • D.R.E.A.M: Divide, Remainder, Estimate, Arithmetic, Multiply - Steps to find square roots!

🎯 Super Acronyms

B.A.R.S

  • Bars for Integral And Decimal Segments.

Flash Cards

Review key concepts with flashcards.

Glossary of Terms

Review the Definitions for terms.

  • Term: Square Root

    Definition:

    A number that produces a specified quantity when multiplied by itself.

  • Term: Division Method

    Definition:

    A systematic method for calculating the square root of a number through division.

  • Term: Remainder

    Definition:

    The amount left over after division when one number cannot be divided by another evenly.