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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 Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ... - Page 28
by Euclid - 1835 - 513 pages

## Mathematics: Compiled from the Best Authors and Intended to be the ..., Volume 2

Mathematics - 1801 - 658 pages
...;• add all the inward angles A, B, C, &c. together, and when the work is right, their sum will be equal to twice as many right angles, as the figure has sides, wanting four right angles. And when there is an angle, as F, that bends inward, and you measure the...

## The Elements of Euclid: Also the Book of Euclid's Data ...cor. viz. The ...

Robert Simson - Trigonometry - 1804 - 530 pages
...CBA, BAC, ACB are equal to two right angles. wherefore if a fide of a triangle, &c. Q^ED . CoR. i. All the interior angles of any rectilineal figure,...equal to twice as many right angles as the figure has fides. For any reCtilineal figure ABCDE can be divided into as many triangles as the figure has fides,...

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

John Playfair, Euclid - Circle-squaring - 1804 - 468 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...

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

Robert Simson - Trigonometry - 1806 - 546 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...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....

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

John Playfair - Mathematics - 1806 - 320 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 four...

## A Course of Mathematics in Two Volumes for the Use of Academies as Well as ...

Charles Hutton - Mathematics - 1807 - 464 pages
...work ; add all the inward angles A, B, c, &c, together ; for when the work is right, their sum will ba equal to twice as many right angles as the figure has sides, wanting 4 right angles. But when there is an angle, as F, that bends inwards, and you measure the external...

## Elements of Geometry, Geometrical Analysis, and Plane Trigonometry: With an ...

Sir John Leslie - Geometry, Analytic - 1809 - 542 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,...

## Elements of Geometry, Geometrical Analysis, and Plane Trigonometry: With an ...

Sir John Leslie - Geometry, Plane - 1809 - 522 pages
...is equal to two right angles. All the exterior angles therefore, added to the interior angles, ftre 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,...