To find the distance between two numbers on a number line, you can take the absolute value of the difference between the two numbers.
In this case, the two numbers are \( 6.5 \) and \( -7.2 \).
First, calculate the difference:
\[ 6.5 - (-7.2) = 6.5 + 7.2 = 13.7 \]
Now, take the absolute value (which is not needed here as the result is already positive):
\[ \text{Distance} = |13.7| = 13.7 \]
Thus, the distance between \( 6.5 \) and \( -7.2 \) on the number line is \( 13.7 \).