Find the value of:
$$\sqrt{3+\sqrt{27+\sqrt{73+\sqrt{64}}}}$$

Solve the expression step-by-step from the innermost square root:
1. Evaluate $\sqrt{64}$:

$$\sqrt{64}=8$$

2. Substitute back into the next expression:

$$\sqrt{73+8}=\sqrt{81}=9$$

3. Substitute back into the next expression:

$$\sqrt{27+9}=\sqrt{36}=6$$

4. Finally, solve the outermost square root:

$$\sqrt{3+6}=\sqrt{9}=3$$