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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

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

Euclides - Geometry - 1841 - 351 pages
...angles. Wherefore, if a side of a triangle, &c. QED COR. 1. 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. For any rectilineal figure ABCDE can be divided into as many triangles as the figure has sides,...

## Elements of geometry: consisting of the first four,and the sixth, books of ...

Euclides - 1842
...triangles ; that is (2. Cor. 13. 1.), together 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....

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

John Playfair - Euclid's Elements - 1842 - 317 pages
...as the figure has sides ; but the exterior are equal to four right angles ; therefore the interior are equal to twice as many right angles as the figure has sides, wanting four. PROP. II. Two straight lines, which make with a third line the interior angles...

## The First Six, and the Eleventh and Twelfth Books of Euclid's Elements: With ...

Euclid, James Thomson - Geometry - 1845 - 352 pages
...equal to two right angles. Wherefore, if a side, &c. Cor. 1. 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. For any rectilineal figure ABCDE can be divided into as many triangles as the figure has sides,...

## Euclid in Paragraphs: The Elements of Euclid: Containing the First Six Books ...

Euclid - Geometry - 1845 - 199 pages
...angles. Wherefore, if a side of a triangle, &c. QED COB. 1. 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 angles of these triangles are equal to twice as many right angles as there are triangles,...

## Euclid's Elements of geometry [book 1-6, 11,12] with explanatory notes ...

Euclides - 1845
...triangles are equal to twice as many right angles as the figure has sides ; 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, made by producing the sides successively...

## The Elements of Euclid, the parts read in the University of Cambridge [book ...

Euclides - 1846
...point F, that is, together with four right angles (1. 15, Cor. 2) : "Wherefore 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....

## Euclid's Elements: Or, Second Lessons in Geometry,in the Order of Simson's ...

Dennis M'Curdy - Geometry - 1846 - 138 pages
...ax. 2 ! (4) p. 27; (c) p. 13. (e)p.29; Cor. 1. All the interior angles of any rectilineal figure and four right angles, are equal to twice as many right angles as the figure has sides. For, about a point within the figure, as many triangles may be formed as the figure has sides,...