Pantometria — A Geometrical Treatize of Measuring

The First Book

An Isosceles triangle is one that has only two sides of equal length, the third being unequal; that unequal side is called the base.

A Scalene Schalenum triangle has three unequal sides.

Three triangles of varying proportions arranged in a row.

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

An Obtuse-angled triangle has one obtuse angle and is called an Ambligonium.

An Acute-angled triangle Oxigonium has all acute or sharp angles.

Three triangles of varying proportions, including a right-angled triangle, arranged in a row.

There are also four-sided figures called Quadrangles, whose opposite sides and angles are equal; such are named Parallelograms, whereof there are but four sorts.

If all the sides are equal and all the angles are right, then that parallelogram is called a Square.

If one side containing the right angle is longer than the other containing side, then that figure is called a Rectangle.

If all the sides are equal and no angle is a right angle, then it is called a Rhombus Rombus.

But if it has only the opposite sides equal, and the other sides that contain an angle are unequal, it shall be named a Rhomboid Romboides.