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?

Read the interior opposite angles on the right of the intersecting line e f.

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

Read the interior alternate angles formed by the lines a b, c d, and e f.

Which pair are acute angles?

Which pair are obtuse angles?

Why are b m n, m n c, interior angles? Why alternate? What are alternate angles?

Read the exterior alternate angles of the same lines.

Read the acute interior alternate angles of the parallels t u, v w. The obtuse.

The acute exterior alternate angles. Obtuse.

Read the pair of opposite exterior angles on the right of the line e f. On the left.

On the right of r s. On the left.

Diagram 15.