Math Problem Statement

The expression \( \frac{1}{\sqrt{27}} - \frac{5\sqrt{3}}{4\sqrt{24}} \) can be written in the form \( a\sqrt{3} - b\sqrt{2} \), with \( a, b > 0 \). To the nearest hundredth, what is the value of \( b \)?

Solution

The expression in question is:

12753424\frac{1}{\sqrt{27}} - \frac{5\sqrt{3}}{4\sqrt{24}}

We need to rewrite this expression in the form:

a3b2a\sqrt{3} - b\sqrt{2}

where aa and bb are constants to be determined, and b>0b > 0.

Let's break this down step-by-step.

Step 1: Simplify 127\frac{1}{\sqrt{27}}

We can simplify this by recognizing that:

27=9×3=33\sqrt{27} = \sqrt{9 \times 3} = 3\sqrt{3}

So:

127=133=39\frac{1}{\sqrt{27}} = \frac{1}{3\sqrt{3}} = \frac{\sqrt{3}}{9}

Step 2: Simplify 53424\frac{5\sqrt{3}}{4\sqrt{24}}

Next, we simplify 53424\frac{5\sqrt{3}}{4\sqrt{24}}. We first note that:

24=4×6=26\sqrt{24} = \sqrt{4 \times 6} = 2\sqrt{6}

So:

53424=534×26=5386\frac{5\sqrt{3}}{4\sqrt{24}} = \frac{5\sqrt{3}}{4 \times 2\sqrt{6}} = \frac{5\sqrt{3}}{8\sqrt{6}}

Now we can multiply both the numerator and denominator by 6\sqrt{6} to rationalize the denominator:

5386×66=5188×6=5×3248=15248=5216\frac{5\sqrt{3}}{8\sqrt{6}} \times \frac{\sqrt{6}}{\sqrt{6}} = \frac{5\sqrt{18}}{8 \times 6} = \frac{5 \times 3\sqrt{2}}{48} = \frac{15\sqrt{2}}{48} = \frac{5\sqrt{2}}{16}

Step 3: Combine the two expressions

Now we have:

395216\frac{\sqrt{3}}{9} - \frac{5\sqrt{2}}{16}

This is already in the desired form a3b2a\sqrt{3} - b\sqrt{2}. From this, we can identify:

a=19,b=516a = \frac{1}{9}, \quad b = \frac{5}{16}

Step 4: Round to the nearest hundredth

Finally, rounding bb to the nearest hundredth:

b0.31b \approx 0.31

Thus, the value of bb is approximately 0.31.

Would you like more details on any of the steps? Let me know if you'd like further clarification!

Here are five related questions:

  1. How do you rationalize a denominator with a square root?
  2. What are other methods to simplify square roots in fractions?
  3. What is the significance of expressing square roots in terms of simpler numbers?
  4. How can you check if a simplified expression is correct?
  5. Can you give another example of a similar problem?

Tip: Always simplify square roots when you encounter them in fractions to make the calculations easier!

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Math Problem Analysis

Mathematical Concepts

Simplifying radicals
Rationalizing denominators
Algebraic manipulation

Formulas

\( \sqrt{a \times b} = \sqrt{a} \times \sqrt{b} \)
\( \frac{1}{\sqrt{a}} = \frac{\sqrt{a}}{a} \)

Theorems

Properties of radicals
Rationalization of denominators

Suitable Grade Level

Grades 9-11