Examples of rational numbers :
1, 1/2, 3/4 , 5 , 6, 15/8 etc
Rational numbers are numbers which can be written as fraction as also that the numerator and denominator are whole examples.
Example 5 can be written as fraction in the form of 5/1.
The answer would be slope
You would at the distances together, since 120 is above sea level and 39 is below. To find the whole vertical distance (the distance they are apart), just add the values (numbers) together.


I hope this helps!
~kaikers
This might help explain how to do a very similar problem.... http://www.mathopenref.com/constbisectline.html