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

Read another pair of exterior alternate angles.

Why are e m a, d n f, alternate angles? Why exterior alternate?

LESSON SIXTEENTH.

REVIEW.

Read the exterior opposite angles on the right of the line e f. (Diagram [14].)

On the left. On the right of r s. On the left.

Why are e m a, c n f, exterior angles?

Why are they opposite angles?

What are opposite angles?