Unit 3 Parallel, Intersecting and Perpendicular lines

Parallel, Intersecting and

Perpendicular lines• Line CD is parallel to line AB.

A B

C D

• Lines that never cross are called parallel lines.

Parallel, Intersecting and

Perpendicular lines• Line EF intersects line AB at point K.

F

A B

K

E

• Intersecting lines are two or more lines that meet at a common point.

Parallel, Intersecting and

Perpendicular lines• Line GH is perpendicular to line AB.

G

A B

E

• Perpendicular lines are lines that intersect each other at right angles.

Lets see if you can tell the difference between parallel, intersecting and

perpendicular….

Parallel

Lets see if you can tell the difference between parallel, intersecting and

perpendicular….

intersecting

Lets see if you can tell the difference between parallel, intersecting and

perpendicular….

Perpendicular

How about this one

Parallel, Intersecting and Perpendicular

So how do we draw perpendicular lines?

• Method 1

• Place a set square on line AB with the right angle touching the line.

A B

So how do we draw perpendicular lines?

• Then draw along the side of the set square that is at right angles to line AB.

A B

Drawing perpendicular lines

• Use your set square to draw lines that are perpendicular to the following lines:

• 1.

Drawing perpendicular lines

• Use your set square to draw lines that are perpendicular to the following lines:

• 2.

Drawing perpendicular lines

• Use your set square to draw lines that are perpendicular to the following lines:

• 3.

Drawing perpendicular lines

• Use your set square to draw lines that are perpendicular to the following lines:

• 4.

What if you don’t have a set square?

• Method 2: Draw a dot (X) on the middle of line AB.

• Place the center of the protractor on the dot

A B

X

What if you don’t have a set square?

• Now draw another dot (Y) at the 90° mark on the protractor.

Y

A B

X

What if you don’t have a set square?

• Draw a line to connect X and Y. Line XY is Perpendicular to line AB.

Y

A B

X