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

Then would there be any greater or less difference of direction?

Then would the angles formed by them be any greater or less?

Then does the size of an angle depend upon the length of the lines that form it?

If the lines a b, e f, were shortened, would the angle formed by them be any smaller?

If two lines form an angle with each other, and meet, the point of meeting is called the vertex.

What is the vertex of the angle formed by the lines k j, i j?—i j, i l?

An angle is named by three letters, that which denotes the vertex being in the middle. Thus, the angle formed by k j, i j, is read k j i, or i j k.

Read the four angles formed by the lines m n and o p.

The eight formed by r s, t u, and v w.