Marks' first lessons in geometry / In two parts. Objectively presented, and designed for the use of primary classes in grammar schools, academies, etc.

by Bernhard Marks

Diagram 13.

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.