Answer: Line must be perpendicular to
Line CF is Line GI .
Step-by-step explanation:
From the given picture, we are given three lines (AD , BE and CF) intersecting other two lines (QI and HJ).
We can see that Line AD and Line CF is making right angle with line GI>
Also, we know that the perpendicular lines intersect at right angles to each other.
Hence, the Line must be perpendicular to
Line CF is Line GI.
