The image shows a math problem where you're asked to evaluate and simplify an expression. The expression given in part (a) is $4 \sqrt{16}$.

Let's solve it step-by-step:

1. Evaluate the square root: $\sqrt{16} = 4$

2. Multiply the result by 4: $4 \times 4 = 16$

So, the simplified expression is 16.

Would you like more details or have any further questions?

Here are five related questions to consider:

1. How would you simplify $5 \sqrt{25}$?
2. What is the general rule for simplifying expressions involving square roots?
3. How do you simplify $3 \sqrt{9}$?
4. What happens if you have $2 \sqrt{4} \times 3$?
5. How can you simplify $6 \sqrt{36}$?

Tip: Always simplify the square root first before multiplying it with any coefficient in front.