Books Books
All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
The London encyclopaedia, or, Universal dictionary of science, art ... - Page 124
edited by

## Elements of Geometry and Trigonometry: With Applications in Mensuration

Charles Davies - 1886 - 340 pages
...triangles is equal to two right angles (Th. xvii) : hence, the sum of the angles of all the triangles is equal to twice as many right angles as the figure has sides. But the sum of all the angles about the point P is equal to four right angles (Th. ii. Cor. 4) ; and...

## The geometry, by T. S. Davies. Conic sections, by Stephen Fenwick

Royal Military Academy, Woolwich - 1853 - 400 pages
...with four right angles. Therefore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. COR. 2. All the exterior angles of any rectilineal figure are together equal to four right angles....

## The first six books of the Elements of Euclid, with numerous exercises

Euclides - 1853 - 176 pages
...with four right angles. Therefore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. Ñîä. 2. All the exterior angles of any rectilineal figure are together equal to four right ,ingles....

## The Elements of Euclid: With Many Additional Propositions ..., Part 1

Euclid - 1853 - 176 pages
...right angles as the figure has sides; but the internal angles, together with four right angles, are equal to twice as many right angles as the figure has sides (6); take away from both the internal angles, and the external angles remain, equal to four right angles...

## The synoptical Euclid; being the first four books of Euclid's Elements of ...

Euclides - 1853 - 146 pages
...with four right angles. Therefore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. COK. 2. — All the exterior angles of any rectilineal figure are together equal to four right angles....

## A Manual for Practical Surveyors: Containing Methods Indispensably Necessary ...

E. W. Beans - 1854 - 114 pages
...taken. If the entire survey has been made as above directed, the sum of all the internal angles will be equal to twice as many right angles as the figure has sides, diminished by four right angles. If this sum, as in practice will be likely to be the case, should...

## Elements of Geometry and Trigonometry from the Works of A.M. Legendre ...

Charles Davies - 1854 - 436 pages
...triangles in the figure ; that is, as many times as there are sides, less two. But this product is equal to twice as many right angles as the figure has sides, less four right angles. Cor. 1. The sum of the interior angles in a quadrilateral is equal to two right...

## The popular educator, Volumes 5-6; Volume 8

Popular educator - 1854 - 922 pages
...into three equal parts. *"'t 3Fig. .42. No. 3. interior angles together with four right angles are equal to twice as many right angles as the figure has sides. Therefore all the interior angles together with all the exterior angles are equal (Ax. 1) to all the...