To find the missing number in the pair "144, ?", let's analyze the other pairs to determine the pattern.

We are given the following pairs:

• (169, 13)
• (49, 7)
• (81, 9)

Notice that in each pair:

• $\sqrt{169} = 13$
• $\sqrt{49} = 7$
• $\sqrt{81} = 9$

It seems that the second number is the square root of the first number.

For the pair (144, ?):

• $\sqrt{144} = 12$

Thus, the missing number is 12.

Would you like further details or have any other questions?

Here are five related questions:

1. Can you determine the missing number in a similar pattern with different numbers?
2. How do square roots relate to other number patterns?
3. Can you think of other mathematical operations that might work for similar puzzles?
4. How would you solve if the relationship involved cubes or higher powers instead of square roots?
5. What happens if the sequence used was based on addition or subtraction instead of roots?

Tip: When tackling number pattern problems, check for simple mathematical relationships like square roots, powers, or arithmetic operations first!