Perpendicular Lines: Numbering in the drawing

Let's remember that perpendicular lines are lines that form a right angle of 90 degrees between them.

Our right angles are:

$ABC,BCD,CDA,DAB$

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 DAB are: DA+AB

Since in a rectangle we have 4 marked angles of 90 degrees, we must have 4 pairs of perpendicular lines.

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.

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

The right angle we have in the drawing is: ABC

The lines that form the angle ABC are: AB+BC

Since we have one marked angle in the triangle, we must have a pair of perpendicular lines.

Let's remember that perpendicular lines form a right angle of 90 degrees between them.

The right angles we have in the drawing are:

$FAB,CDE$

The lines that create the angle FAB are: FA + AB

The lines that create the angle CDE are: CD + DE

Since we have 2 angles marked in the diagram, we therefore also have 2 pairs of perpendicular lines.

Let's remember that perpendicular lines are lines that form a right angle of 90 degrees between them.

Our right angles are:

$BAE,DEA$

The lines that form angle BAE are: BA+AE

The lines that form angle DEA are: DE+EA

Since in the drawing we have 2 angles of 90 degrees marked, we must have 2 pairs of perpendicular lines.

Let's remember that perpendicular lines are lines that form a right angle of 90 degrees between them.

Let's draw straight lines extending from each of the four vertices of the shape to examine whether the angles are right angles.

The drawing will look like this:

From the drawing, we can see that angles DAB+CBA are greater than 90 degrees, while angles ADC+DCB are less than 90 degrees.

Since no right angles are marked in the drawing, there are 0 pairs of perpendicular lines in the drawing.

Let's remember that perpendicular lines are straight lines that create a right angle of 90 degrees at their intersection point.

Let's locate the intersection points that create the right angles in the drawing.

The lines that create the right angles are:

AB is perpendicular to BC

BC is perpendicular to CD

CD is perpendicular to DA

DA is perpendicular to AB

BC is perpendicular to EF

AD is perpendicular to EF

Therefore, in the drawing there are 6 perpendicular lines.

Let's remember that perpendicular lines are straight lines that create a 90-degree angle at their intersection point.

Let's locate the intersection points that create right angles in the drawing:

The lines that create the marked right angles are:

AB is perpendicular to CD

AB is perpendicular to EF

EF is perpendicular to IJ

IJ is perpendicular to GH

Therefore, there are 4 perpendicular lines in the drawing.