To find the number of subsets of a given set, we use the formula:

$\text{Number of subsets} = 2^n$

where $n$ is the number of elements in the set.

In the given set $\{4, 3, 9\}$, there are 3 elements. So, we have:

$\text{Number of subsets} = 2^3 = 8$

Therefore, the number of subsets of the set $\{4, 3, 9\}$ is 8.

Would you like more details or have any questions?

Here are 5 related questions to expand your understanding:

1. How many subsets does a set with 4 elements have?
2. What is the number of proper subsets of a set with 3 elements?
3. How do you find the number of subsets of a set with no elements (an empty set)?
4. What are the subsets of the set $\{1, 2\}$?
5. How does the number of elements in a set affect the number of subsets?

Tip: The subset count includes both the empty set and the set itself.