Counting Perpendicular Lines: Identifying Right Angle Pairs in a Geometric Diagram

Let's remember that perpendicular lines are lines that intersect at a right angle of 90 degrees.

Our right angles are:

$ABC,BCD,CDE,DEF,EFA,FAB$

The lines that form angle ABC are: AB+BC

The lines that form angle BCD are: BC+CD

The lines that form angle CDE are: CD+DE

The lines that form angle DEF are: DE+EF

The lines that form angle EFA are: EF+FA

The lines that form angle FAB are: FA+AB

Since in the drawing we have 6 angles of 90 degrees marked, we must have 6 pairs of perpendicular lines.