Answered

Simplify the radical: $\sqrt{ 1 8 0 }$


A$6 \sqrt{5}$
B$9 \sqrt{20}$
C$2 \sqrt{90}$
D$18 \sqrt{10}$

Verified Answer :

  • Prime factorize 180 to find the largest perfect square factor: \(180 = 36 \times 5\).
  • Apply the radical property \(\sqrt{a \cdot b} = \sqrt{a} \cdot \sqrt{b}\) to isolate the square root: \(\sqrt{36 \cdot 5} = \sqrt{36} \cdot \sqrt{5}\).
  • Simplify the expression: \(6\sqrt{5}\).
  • Match the result to the options provided: \(\boxed{\text{(A)}}\).

Explanation

  1. Factorizing 180

To simplify the radical \(\sqrt{180}\), we aim to express the number under the square root, 180, as a product of a perfect square and another factor. This allows us to use the property \(\sqrt{x \cdot y} = \sqrt{x} \cdot \sqrt{y}\). First, we perform prime factorization of 180:
\[180 = 18 \times 10 = (2 \times 9) \times (2 \times 5) = 2 \times 3^2 \times 2 \times 5 = 2^2 \times 3^2 \times 5 = 4 \times 9 \times 5 = 36 \times 5.\]
We identify 36 as the largest perfect square factor.

  1. Simplifying the Radical

Using the property \(\sqrt{x \cdot y} = \sqrt{x} \cdot \sqrt{y}\), we can rewrite the expression:
\[\sqrt{180} = \sqrt{36 \times 5} = \sqrt{36} \cdot \sqrt{5}.\]
Since the square root of 36 is 6, we have:
\[\sqrt{36} \cdot \sqrt{5} = 6\sqrt{5}.\]
Thus, the simplified form of \(\sqrt{180}\) is \(6\sqrt{5}\).

  1. Evaluating the Choices

Now we compare our result with the given choices:

A\(6\sqrt{5}\)
B\(9\sqrt{20}\)
C\(2\sqrt{90}\)
D\(18\sqrt{10}\)

We have already found that \(\sqrt{180} = 6\sqrt{5}\), which matches option (A). We can verify the others:

  • (B) \(9\sqrt{20} = \sqrt{81 \times 20} = \sqrt{1620}\)
  • (C) \(2\sqrt{90} = \sqrt{4 \times 90} = \sqrt{360}\)
  • (D) \(18\sqrt{10} = \sqrt{324 \times 10} = \sqrt{3240}\)

None of these are equal to \(\sqrt{180}\). Therefore, the correct choice is (A).

Examples

Simplifying radicals is essential in many fields, including architecture and construction. For instance, if you need to calculate the length of a diagonal in a rectangular garden measuring \(\sqrt{180}\) units, you can use the simplified form to make measurements much more manageable. Instead of working with an unwieldy number, you can express it as \(6\sqrt{5}\), which helps you estimate or calculate precise dimensions more easily in your projects.