Perpendicular Line Identification in Rectangle with Parallel Lines

How many pairs of perpendicular lines are shown in the diagram?

Remember that perpendicular lines are lines that form a right angle of 90 degrees between them.

We will draw straight lines coming from each of the marked points in the figure to examine whether the angles are right angles.

The drawing will look like this:

Note that the lines we drew create right angles, which are:

$BAD,ABC,BCD,CDA,GEF,EGH,GHF,HFE$

The lines that form angle BAD are: BA+AD

The lines that form angle ABC are: AB+BC

The lines that form angle BCD are: BC+CD

The lines that form angle CDA are: CD+DA

The lines that form angle GEF are: GE+EF

The lines that form angle EGH are: EG+GH

The lines that form angle GHF are: GH+HF

The lines that form angle HFE are: HF+FE

Given that in the drawing we have 8 angles of 90 degrees marked, we must have 8 pairs of perpendicular lines.