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

Diagram 20.

QUADRILATERALS.

How many sides has the figure a b d c?

What is it called on account of the number of its sides?

Name three other quadrilaterals whose vertices are marked.

Name seven by numbers.

Quadrilaterals are sometimes named by means of two opposite vertices.

The quadrilateral a b d c, or c d b a, may be read a d, or b c, or c b, or d a.

Name the quadrilateral, g h f e, four ways.

How many angles has each figure?