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

Two pairs of alternate exterior angles.

Why are the angles i o m, m o j, called adjacent?

What are adjacent angles?

What kind of an angle is i o m? Why?

What is an acute angle?

What kind of an angle is m o j? Why?

What is an obtuse angle?

Why are a c f, f c b, right angles?

What is a right angle?

Why are m o i, j o p, vertical angles?