Chapter 17, Problem 1RE

To determine

The parallel lines from the Figure 17-135.

Answer to Problem 1RE

The lines $\underset{\_}{\overleftrightarrow{AB}\text{ and }\overleftrightarrow{CD}}$ are parallel lines.

Explanation of Solution

Note that two lines $\overleftrightarrow{AB}\text{ and }\overleftrightarrow{CD}$ does not intersect each other.

And they maintain the same distance over their entire length and hence they never touch each other.

Therefore, $\overleftrightarrow{AB}\text{ and }\overleftrightarrow{CD}$ are called parallel lines and it is denoted by $\overleftrightarrow{AB}\text{ ||}\overleftrightarrow{CD}$.

Thus, $\underset{\_}{\overleftrightarrow{AB}\text{ and }\overleftrightarrow{CD}}$ are parallel lines.