To determine the distance between two numbers on a number line, you can use the formula for distance:
\[ \text{Distance} = |a - b| \]
where \(a\) and \(b\) are the two numbers. In this case, \(a = 6.5\) and \(b = -7.2\).
Now, let's calculate it:
\[ \text{Distance} = |6.5 - (-7.2)| = |6.5 + 7.2| = |6.5 + 7.2| \]
Now we add the numbers:
\[ 6.5 + 7.2 = 13.7 \]
Thus, the distance between 6.5 and -7.2 is:
\[ |6.5 - (-7.2)| = |13.7| = 13.7 \]
Therefore, the correct response is:
13.7