To find the distance between two numbers on a number line, you can use the formula:
\[ \text{Distance} = |a - b| \]
where \( a \) and \( b \) are the two numbers. In this case, the numbers are 6.5 and -7.2.
Calculating the distance:
\[ \text{Distance} = |6.5 - (-7.2)| = |6.5 + 7.2| = |6.5 + 7.2| = |13.7| \]
Therefore, the distance between 6.5 and -7.2 is \( 13.7 \).
The correct answer is:
13.7