Semicircle on a Rectangle's Base plus Height; a Pythagorean Figure
A mean-proportional construction and a figure for the theorem of Pythagoras
A faint pencil page of Euclidean geometry. One figure raises a semicircle on the sum of the base and height of a rectangle, annotated with the values 6, 36 and 18 and a cross-reference "by the fifth [proposition]." A further figure is described as corresponding to the theorem of Pythagoras. The drawings are lightly sketched in pencil.
On this page
Semicircle raised on base plus height
A semicircle is constructed on a line equal to the sum of a rectangle's base and its height, the classic way of finding a mean proportional. The numbers 6, 36 and 18 accompany it, with a reference "by the fifth" pointing back to an earlier proposition.
Figure for the theorem of Pythagoras
A separate figure is set out to illustrate the theorem of Pythagoras, relating the squares on the sides of a right triangle. It is drawn faintly in pencil alongside the semicircle construction.