Chapter 10: Problem 20
Simplify completely. If the radical is already simplified, then say so. $$\sqrt{108}$$
Short Answer
Expert verified
The simplified expression for \( \sqrt{108} \) is \( 6\sqrt{3} \).
Step by step solution
01
Find the prime factors of 108
To simplify \( \sqrt{108} \), first find the prime factors of 108. The prime factors are the prime numbers that can be multiplied together to give the original number. We can use a process called prime factorization:
$$
108 = 2 \times 54 \\
= 2 \times (2 \times 27) \\
= 2 \times 2 \times (3 \times 9) \\
= 2^2 \times 3 \times (3^2)
$$
So, the prime factorization of 108 is: \( 2^2 \times 3^3 \).
02
Factor out any square factors
Look for any square factors in the prime factorization of 108. A square factor is any number that appears in the prime factorization with an exponent that is a multiple of 2.
In the prime factorization of 108: \(2^2 \times 3^3\), we notice that \(2^2\) is a square factor.
03
Simplify the square root
Factor out the square factor from the square root. Then, simplify the expression.
Take the square root of the square factor: \(\sqrt{2^2} = 2\)
Now, divide the original exponent by 2:
$$
3^3 = 3^{(3 \div 1)} = 3^1
$$
Finally, multiply the results together:
$$
\sqrt{108} = 2 \times 3^1 = 2 \times 3 = 6\sqrt{3}
$$
The simplified expression for \( \sqrt{108} \) is \( 6\sqrt{3} \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Prime Factorization
To simplify a square root effectively, it's crucial to understand the concept of prime factorization. Prime factorization is breaking down a number into prime numbers that, when multiplied together, give back the original number. A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. For example, the numbers 2, 3, 5, and 7 are primes because they cannot be divided evenly by any other number except 1 and themselves.
Here's how you can perform prime factorization:
108 is divided by 2 (the smallest prime number), yielding 54.
54 can be divided by 2 again, which results in 27.
Switch to the next smallest prime, 3. Divide 27 by 3 to get 9, and finally, divide 9 by 3 twice to obtain 1. Hence, the factorization becomes:
\[108 = 2^2 \times 3^3 \]
This step is foundational for simplifying square roots.
Here's how you can perform prime factorization:
- Start by dividing the number by the smallest prime, which is 2. Keep dividing by 2 until you can't anymore.
- Next, try the next smallest prime, which is 3, then 5, and so on, until the only remaining number is 1.
108 is divided by 2 (the smallest prime number), yielding 54.
54 can be divided by 2 again, which results in 27.
Switch to the next smallest prime, 3. Divide 27 by 3 to get 9, and finally, divide 9 by 3 twice to obtain 1. Hence, the factorization becomes:
\[108 = 2^2 \times 3^3 \]
This step is foundational for simplifying square roots.
Square Factors
Once you've found the prime factors, the next step is to identify the square factors. A square factor refers to any factor of a number that can be expressed as a square of an integer. In the context of simplifying radicals, it means looking for numbers in the prime factorization that can be expressed as some prime's power of 2 or higher.
In our example with 108:
In our example with 108:
- We have \(2^2\), which is a square because it's the same as \(2\times2\).
- The 3s are left unpaired without forming a square factor since \(3^3 = 3\times3\times3\), where only \(3^2\) can be paired to form a square.
Radicals
Radicals are symbols that represent the root of a number, with the most common being the square root. In mathematical notation, a square root is denoted by the radical sign (\(\sqrt{}\)). Simplifying radicals involves reducing the expression under the radical sign to its simplest form. This process ties closely with prime factorization and identifying square factors.
Here's a step-by-step on simplifying a radical:
\[\sqrt{108} = \sqrt{2^2 \times 3^3} = 2 \times \sqrt{3^3} = 2 \times 3 \times \sqrt{3} = 6\sqrt{3}\].
Thus, simplifying radicals by using prime factorization and identifying square factors can make seemingly complex expressions much more manageable.
Here's a step-by-step on simplifying a radical:
- Factor the number inside the radical into its prime factors.
- Look for square factors, which are pairs of the same number, under the radical sign.
- Take the square root of these squares, essentially moving them outside the radical.
\[\sqrt{108} = \sqrt{2^2 \times 3^3} = 2 \times \sqrt{3^3} = 2 \times 3 \times \sqrt{3} = 6\sqrt{3}\].
Thus, simplifying radicals by using prime factorization and identifying square factors can make seemingly complex expressions much more manageable.