If our net income on December 31st, 2015 was $4500, and our sales were $42080, what is our profit margin? What does this tell us?

To calculate the financial metrics you asked about, let's start with what we have:

- **Net Income**: $4,500
- **Sales**: $42,080

### 1. Profit Margin
The formula for profit margin is:
\[
\text{Profit Margin} = \left( \frac{\text{Net Income}}{\text{Sales}} \right) \times 100
\]
Substituting the values:
\[
\text{Profit Margin} = \left( \frac{4,500}{42,080} \right) \times 100 \approx 10.65\%
\]
### Interpretation:
A profit margin of approximately 10.65% means that for every dollar in sales, there is about 10.65 cents in profit after all expenses are deducted. A profit margin above 10% suggests a healthy business with effective cost management relative to revenue.

### 2. Return on Assets (ROA)
To calculate ROA, you'll need total assets. If we assume an example total asset figure (you did not provide this), the formula is:
\[
\text{ROA} = \left( \frac{\text{Net Income}}{\text{Total Assets}} \right) \times 100
\]
Let's assume total assets are $30,000 (you’ll need to substitute this with the actual figure for precise results):
\[
\text{ROA} = \left( \frac{4,500}{30,000} \right) \times 100 = 15\%
\]
### Interpretation:
A ROA of 15% indicates that the company is generating $0.15 of profit for every dollar of assets owned. A higher ROA indicates better efficiency in utilizing assets to generate profit.

### 3. Current Ratio
The current ratio measures a company's ability to pay short-term obligations. The formula is:
\[
\text{Current Ratio} = \frac{\text{Current Assets}}{\text{Current Liabilities}}
\]
You will need the values for current assets and current liabilities to perform this calculation.

### Interpretation:
A current ratio greater than 1 indicates that the company has more current assets than current liabilities, which suggests good short-term financial health. A ratio below 1 may indicate potential liquidity problems.

### 4. Debt to Total Assets
This ratio shows the proportion of a company's assets that are financed by debt. The formula is:
\[
\text{Debt to Total Assets} = \frac{\text{Total Liabilities}}{\text{Total Assets}}
\]
You’ll need total liabilities and total assets for this calculation.

### Interpretation:
A higher ratio means that a larger portion of company assets is financed by debt, which can indicate higher risk. Conversely, a lower ratio suggests a more financially stable position with less reliance on borrowed funds.

### Summary
To accurately calculate the Return on Assets, Current Ratio, and Debt to Total Assets, you will need additional financial data beyond what has been provided, specifically total assets, current assets, current liabilities, and total liabilities.