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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.
Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books - Page 56
by Euclid - 1765 - 464 pages

## Elements of Geometry;: Containing the First Six Books of Euclid, with a ...

Euclid, John Playfair - Circle-squaring - 1804 - 440 pages
...Wherefore^ if a fide of a triangle; &c. C^ED CoR. i. All the interior angles of any reftilmeal figure, are equal to twice as many right angles as the figure has fides, wanting four right angles. For any reftilineal figure ABCDE can be divided into as many triangles as...

## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1806 - 518 pages
...the triangles ; that is », to15. 1. gether 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...

## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - Euclid's Elements - 1806 - 311 pages
...to all the angles of the figure, together with four right angles, that is, the angles of the figure are equal to twice as many right angles as the figure has sides, wanting four. COR. 2. All the exterior angles of any rectilineal figure are together equal to...

## The Accomplished Tutor; Or, Complete System of Liberal Education ..., Volume 1

Thomas Hodson - Arithmetic - 1806 - 458 pages
...work ; — add all the inward angles ABC, &c. together ; and if the work be right, the fum will be equal to twice as many right angles as the figure has fides, except four right angles ; but when there is an angle that bends inwards, as at F, and you meafure...

## Elements of Geometry, Geometrical Analysis, and Plane Trigonometry ...

Sir John Leslie - Geometry, Analytic - 1809 - 524 pages
...interior one AED, is equal to two right angles. All the exterior angles therefore, added to the interior angles, are equal to twice as many right angles as the figure has sides. Consequently the exterior angles are equal to the four right angles which, by the last Proposition,...

## The Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclid - Geometry - 1810 - 518 pages
...a side of a triangle, &c. QED CoR. 1. All the interior angles of any rectilineal figure, together D with four right angles, are equal to twice as many right angles as the figure has sides. For any rectilineal figure ABCDE can be divided into as many triangles as the figure has .sides,...

## The Elements of Euclid; viz. the first six books, together with the eleventh ...

Euclides - 1814
...the same angles are equal to the angles of the figure, together with the angles at the point F, which 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 Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclides - 1816 - 528 pages
...the triangles : that is a, together is. 1. 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...