10-10-2013 Opposite Angles

I will be out tomorrow and you will have a substitute teacher.  Be good!

Fold a line on your patty paper.
Unfold.
Fold a second line INTERSECTING (crossing) the first line.

With your pencil, label the angles 1,2,3,4 as shown above.

Angle 1 and 3 are opposite angles.  They are also called vertical angles.

Which other two angles are vertical angles on your patty paper?

What do you notice about vertical angles?