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

ISOSCELES TRIANGLES.

Of the triangle 1, which two sides are equal to each other?

Then it is called an isosceles triangle.

An isosceles triangle is one that has two equal sides.

Name eight isosceles triangles.

Why is the triangle 2 an isosceles triangle?

What kind of a triangle is it on account of its angles?

Then it is an acute-angled isosceles triangle.

Name four acute-angled isosceles triangles.

What kind of a triangle is Fig. 4 on account of the angle k j l?