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

Why is it perpendicular to it?

What line is perpendicular to z 1?

When is a line said to be perpendicular to another?

Can a line standing alone be properly called a perpendicular line?

What two lines are perpendicular to the lines r s?

Is the line g h perpendicular to the line i j? Why?

What other line is perpendicular to the line i j?

Read three lines that are perpendicular to the line a b.

PARALLEL LINES.

Do the lines k l, m n, differ in direction? Then do they form any angle with each other?