LESSON THIRTEENTH.
RELATIONS OF ANGLES.
INTERIOR ANGLES.
Is the angle a m n between the parallels, or outside of them? (Diagram [13].)
It is called an interior angle.
Read three other interior angles between the same parallels.
Why is b m n an interior angle?
An interior angle is one that lies between parallel lines.
Read the interior angles between the parallel lines g h and k l.
Why is o p l an interior angle?
What is an interior angle?
EXTERIOR ANGLES.
Is the angle a m e between the parallels, or outside of them?
It is called an exterior angle.
Read three other exterior angles formed by the lines a b, c d, and e f.
Why is the angle c n f an exterior angle?
An exterior angle is one that lies outside of the parallels.
