To determine the distance between -17.45 and 1.35 on the number line, we use the formula for distance between two numbers \( a \) and \( b \):
\[ \text{Distance} = |a - b| \]
In this case, let \( a = -17.45 \) and \( b = 1.35 \).
Now, we calculate:
\[ \text{Distance} = |-17.45 - 1.35| \]
Calculating the expression inside the absolute value:
\[ -17.45 - 1.35 = -18.80 \]
Now take the absolute value:
\[ |-18.80| = 18.80 \]
Thus, the distance between -17.45 and 1.35 on the number line is 18.80.
Given the options -16.1, -18.75, 18.8, and 18.85, the closest correct answer is:
18.8.