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

A right-angled triangle is one that has one right angle.

Name three other right-angled triangles.

Upon which side does the triangle 3 seem to stand?

Then i j is called the base of the triangle.

What letter marks the vertex of the angle opposite the base?

Then the point g is said to be the vertex of the triangle.

If, in the triangle 7, we consider t v the base, what point is the vertex?

If v be considered the vertex, which side will be the base?

In the triangle 3, what side is opposite the right angle?

Then g j is called the hypothenuse of the triangle.