To find the ratio of the number of male teachers to the number of female teachers at Rosanne's high school, we can use the following formula for ratios:
\[ \text{Ratio} = \frac{\text{Number of Male Teachers}}{\text{Number of Female Teachers}} \]
In this case:
- Number of Male Teachers = 19
- Number of Female Teachers = 2
Now, we can substitute these values into the formula:
\[ \text{Ratio} = \frac{19}{2} \]
This ratio can also be expressed in the form of "X:Y", where X is the number of male teachers and Y is the number of female teachers:
\[ \text{Ratio} = 19:2 \]
So, the ratio of the number of male teachers to the number of female teachers is 19:2.