The problem is to evaluate the expression $\sqrt{49 \times 81}$.

1. Problem Description

The problem is to evaluate the expression $\sqrt{49 \times 81}$.

2. Solution Steps

We can evaluate this expression by first finding the square root of each number individually and then multiplying them.

We have:

$\sqrt{49} = 7$

$\sqrt{81} = 9$

Then we multiply these two results:

$7 \times 9 = 63$

Alternatively, we can multiply the numbers first and then find the square root.

$49 \times 81 = 3969$

$\sqrt{3969} = 63$

3. Final Answer

The final answer is 63.