1. The problem is to understand if the expression "5:12" is in ratio form. 2. A ratio compares two quantities and is written as $a:b$ where $a$ and $b$ are numbers. 3. The expression "5:12" fits this format, where $a=5$ and $b=12$. 4. Therefore, "5:12" is indeed a ratio comparing 5 parts to 12 parts. 5. Ratios can also be expressed as fractions, so $5:12$ is equivalent to $\frac{5}{12}$. 6. This means for every 5 units of one quantity, there are 12 units of another quantity. Final answer: Yes, 5:12 is a ratio form.