The given expression is $\sqrt{\dfrac{49}{81}}$.

To solve this:

1. The square root of a fraction can be written as the square root of the numerator divided by the square root of the denominator:

$\sqrt{\dfrac{49}{81}} = \dfrac{\sqrt{49}}{\sqrt{81}}$

2. Now, calculate the square roots:

$\sqrt{49} = 7 \quad \text{and} \quad \sqrt{81} = 9$

3. Therefore:

$\sqrt{\dfrac{49}{81}} = \dfrac{7}{9}$

So, $\sqrt{\dfrac{49}{81}} = \dfrac{7}{9}$.

Do you want details or have any questions?

Here are 5 related questions you might find useful:

1. What is $\sqrt{\dfrac{16}{25}}$?
2. Simplify $\sqrt{\dfrac{64}{100}}$.
3. Calculate $\sqrt{\dfrac{36}{49}}$.
4. Find the value of $\dfrac{\sqrt{25}}{\sqrt{81}}$.
5. What is $\dfrac{9}{7} \times \sqrt{\dfrac{49}{81}}$?

Tip: To simplify square roots of fractions, remember to take the square root of the numerator and denominator separately.