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

On account of the number of their angles they are called quadrangles.

Has the quadrilateral a d any two sides parallel to each other?

Then it is called a trapezium.

A trapezium is a quadrilateral that has no two sides parallel.

Name two other trapeziums.

Why is Fig. 7 a trapezium?

Has the quadrilateral e h any two sides parallel? Which two? Are the other two sides parallel?

It is called a “trapezoid.”

“Oid” means like. What does “trapezoid” mean?

A trapezoid is a quadrilateral that has only one pair of sides parallel.