Perpendicular Lines: True / false

As we know, in a rectangle all angles are equal to 90 degrees.

Let's mark all the angles in the rectangle:

Now, let's find the intersection point of side BD and side DC and draw T as follows:

We should note that indeed the lines form a 90-degree angle, and therefore the lines are perpendicular.

Let's remember that parallel lines are two straight lines that lie in the same plane and never intersect (do not cross).

Let's draw all the right angles in the drawing, and extend the lines to create parallel lines, as follows:

We saw that we marked 8 right angles in the drawing, now let's mark each pair of parallel lines:

Note that in the drawing we marked 6 pairs of parallel lines.

Remember that perpendicular lines are lines that intersect at a 90-degree angle.

Let's mark the right angles in the drawing:

We can see that we have 4 pairs of perpendicular lines:

AE is perpendicular to AB

BF is perpendicular to AB

AE is perpendicular to EC

BF is perpendicular to FD

Let's remember that perpendicular lines are lines that intersect at a 90-degree angle.

According to the properties of the square, all angles measure 90 degrees and the diagonals are bisectors.

We will focus on the upper triangle formed by the diagonals intersecting each other.

Since all angles measure 90 degrees, the diagonals form two 45-degree angles.

We will draw this as follows:

Calculate the missing third angle in the triangle, marked with a question mark, as follows.

The sum of the angles of a triangle equals 180 degrees, so the formula to find the third angle is:

$180-45-45=$

$180-45=135$

$135-45=90$

Since the third angle equals 90 degrees, its complementary angle also equals 90 degrees:

Since the diagonals form a 90-degree angle between them, they are indeed perpendicular and perpendicular to each other.

Let's remember that perpendicular sides create a 90-degree angle between them.

We will draw a 90-degree angle at each intersection of the sides as follows:

From the figure, we notice that there is not a single angle that is not right.

Remember that perpendicular lines are lines that form a 90-degree angle.

We will examine this by drawing the letter T at the intersection point of lines AB and BC as follows:

It seems from the drawing that the angle formed between the lines is a right angle, therefore side AB is indeed perpendicular to side BC.

Remember that perpendicular lines form a 90-degree angle.

We will mark on the figure all the right angles formed by the intersections of the lines as follows:

The figure shows that there are 12 right angles, therefore there are 12 pairs of perpendicular lines.

Remember that perpendicular lines form a 90-degree angles.

As we know, in the cube all angles are 90 degrees (right angles).

We will mark the angles of the highlighted face in the following way:

As a cube has 6 faces, we will multiply the number of angles we marked by 6 to get:

$4\times6=24$

Therefore, the number of perpendicular lines in a cube is 24.

Remember that perpendicular lines form a 90-degree angle.

We will mark the intersection points of the lines with the letter T to work out if the angles are right angles, as follows:

From the drawing, it seems there are 2 right angles, which means there are indeed 2 pairs of perpendicular lines.