Write in simplest radical form: a) 1/3√63 + 2/5√700 - 2/3√112 + 3/2√28; b) 7/2√1024 + 5/12√2000 - 3√686 + 1/8√128. Determine the perimeter of the figures: a) √45, √45, √20, √125; b... Write in simplest radical form: a) 1/3√63 + 2/5√700 - 2/3√112 + 3/2√28; b) 7/2√1024 + 5/12√2000 - 3√686 + 1/8√128. Determine the perimeter of the figures: a) √45, √45, √20, √125; b) 2√80 + √24 - 2√96 + 5√125.

Question image

Understand the Problem

The question is asking to simplify radical expressions and determine the perimeter of given geometric figures represented in radical form.

Answer

Answer for screen readers

The simplified answers are: a) $ \frac{16}{3} \sqrt{7} $
b) $ 36 + \frac{25}{6} - 3 \sqrt[3]{686} $
Perimeter for figure a) is $ 2(\sqrt{45} + \sqrt{20}) $
Perimeter for figure b) is $ 2 (\sqrt{80} + \sqrt{24}) - 2(\sqrt{96} + \sqrt{125}) $

Steps to Solve

  1. Simplifying the terms
    First, we simplify each radical expression in the given problems.

    For part a, we start with:

    • $ \frac{1}{3} \sqrt{63} = \frac{1}{3} \cdot 3\sqrt{7} = \sqrt{7} $
    • $ \frac{2}{5} \sqrt{700} = \frac{2}{5} \cdot 10\sqrt{7} = 4\sqrt{7} $
    • $ -\frac{2}{3} \sqrt{112} = - \frac{2}{3} \cdot 4\sqrt{7} = -\frac{8}{3}\sqrt{7} $
    • $ \frac{3}{2} \sqrt{28} = \frac{3}{2} \cdot 2\sqrt{7} = 3\sqrt{7} $

    Now combine like terms:
    $$ \sqrt{7} + 4\sqrt{7} - \frac{8}{3}\sqrt{7} + 3\sqrt{7} $$

  2. Finding a common denominator
    We need a common denominator to combine the coefficients of $\sqrt{7}$. The common denominator is 3:

    $$ \sqrt{7} = \frac{3}{3}\sqrt{7} $$
    $$ 4\sqrt{7} = \frac{12}{3}\sqrt{7} $$
    $$ 3\sqrt{7} = \frac{9}{3}\sqrt{7} $$

    Combining all parts gives:
    $$ \frac{3 + 12 - 8 + 9}{3} \sqrt{7} = \frac{16}{3} \sqrt{7} $$

  3. Simplifying part b
    Next, simplify part b:

    • $ \frac{7}{2} \sqrt[3]{1024} = \frac{7}{2} \cdot 10 = 35 $
    • $ \frac{5}{12} \sqrt[3]{2000} = \frac{5}{12} \cdot 10 = \frac{50}{12} = \frac{25}{6} $
    • $ -3 \sqrt[3]{686} \text{ (no simplification possible, keep as is)} $
    • $ \frac{1}{8} \sqrt[3]{128} = \frac{1}{8} \cdot 8 = 1 $

    Thus, combining gives:
    $$ 35 + \frac{25}{6} - 3 \sqrt[3]{686} + 1 $$
    To combine $35 + 1$, results in:
    $$ 36 + \frac{25}{6} - 3 \sqrt[3]{686} $$

  4. Calculating the perimeter
    Now let’s determine the perimeter of the geometric figures.

    For figure a, with dimensions $ \sqrt{45} \times \sqrt{45} \times \sqrt{20} \times \sqrt{125} $, the perimeter $P$ is calculated as: $$ P = 2(\sqrt{45} + \sqrt{20}) $$

    For figure b:
    The expressions to calculate perimeter:
    $$ P = 2 (\sqrt{80} + \sqrt{24}) - 2(\sqrt{96} + \sqrt{125}) $$

  5. Final calculations
    Compute simplified versions of the perimeter from the two figures after simplifications.

The simplified answers are: a) $ \frac{16}{3} \sqrt{7} $
b) $ 36 + \frac{25}{6} - 3 \sqrt[3]{686} $
Perimeter for figure a) is $ 2(\sqrt{45} + \sqrt{20}) $
Perimeter for figure b) is $ 2 (\sqrt{80} + \sqrt{24}) - 2(\sqrt{96} + \sqrt{125}) $

More Information

Radical expressions can often be simplified by finding factors that are perfect squares (or cubes, etc. for cube roots). The perimeter of figures can similarly rely on calculating the sum of all sides simplified to simplest radical form.

Tips

  • Forgetting to simplify radicals as much as possible. Always look for perfect squares or cubes in the expressions.
  • Not combining like terms correctly, especially with different coefficients.
  • Using incorrect braces or parentheses in calculations can lead to wrong expressions.
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