Parallel and Pendicular lines

Parallel and Perpendicular lines

Geometry- Shapes and measurements.

Parallel- Describes two lines in the same plane that never cross, or intersect.
- They are marked using arrows.


Here is a picture of parallel lines:


Perpendicular- Describes lines that intersect at right angles. ( 90°)
- They are marked using a small square
Here's a picture of a right angle

Measure the difference from:

A to B
B to C
E to F
F to G
I to J
J to K
They all are 8.9 cm.

Here's a video about Perpendicular lines


Here's the link: http://www.youtube.com/watch?v=Lc3dPkoCOHc

Identify any parallel lines you can find.
AE // BF, EI // FJ, CG // BF, GK // JF, AI // CK


What d0 you notice about parallel lines? they always are the same distance apart no matter where you measure, as long as you measure a perpendicular line.


Identify any perpendicular line segments.


AE __ DF , FE __ AI , BF __ EG , CG __ FH

What do you notice about perpendicular line segments? they all meet at 90° angles.

FOR HOMEWORK!
#1. Are line segments AC and DF parallel?
#2. Are line segments DF and BE perpendicular?
#3. Are line segments AC and BE perpendicular? How do you know?
#4. Would a line segment joining A to D be parallel to a line segment BE? How do you know?