The sequence is: 64, 45, ___, 25. We need to identify the pattern in order to determine the missing number.

Let's analyze the differences between the numbers:

1. Difference between 64 and 45: $64 - 45 = 19$

2. Difference between 45 and the next number (let's call it $x$): $45 - x = d_2$

3. Difference between $x$ and 25: $x - 25 = d_3$

Since the differences are usually consistent or follow a pattern, let's assume the difference $d_2$ equals $d_3$, or at least close to it. To test this:

Let's try assuming $d_2 = d_1 = 19$:

If $45 - x = 19$, then: $x = 45 - 19 = 26$

But 26 is not in the options. However, since the last difference could be slightly different, try $x - 25 = d_2$.

Let's consider the possibility that the difference might reduce consistently (like an arithmetic sequence with decreasing differences). If the first difference is 19, let's see if the next difference is slightly less, like 16:

If $x = 29$ then: $45 - 29 = 16 \quad \text{and} \quad 29 - 25 = 4$

These differences suggest that 29 could be a reasonable answer.

Therefore, the correct choice is: $\boxed{29}$

Would you like a deeper explanation or have any questions?

Related Questions:

1. How do arithmetic sequences differ from geometric sequences?
2. Can we find a general formula for this sequence if given more terms?
3. How would this sequence change if it were based on a different pattern, like multiplication?
4. What are common techniques to identify patterns in number sequences?
5. How can differences between terms help in identifying the rule of a sequence?

Tip: In sequences, always check for both arithmetic and geometric patterns when the rule is not immediately clear.