To find the total balance of liabilities, we can use the accounting equation:
\[ \text{Assets} = \text{Liabilities} + \text{Net Worth} \]
Given that the total assets are $45,000 and the net worth is $25,000, we can rearrange the equation to solve for liabilities:
\[ \text{Liabilities} = \text{Assets} - \text{Net Worth} \]
Now, substituting in the values:
\[ \text{Liabilities} = 45,000 - 25,000 = 20,000 \]
Thus, the total balance of liabilities is $20,000.