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Cor. angles; that is * together with four right angles. There1s, 1. fore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
The Elements of Euclid: The Errors by which Theon, Or Others, Have Long ... - Page 28
by Robert Simson - 1827 - 513 pages

## A Course of Mathematics ...: Composed for the Use of the Royal Military ...

Charles Hutton - Mathematics - 1811 - 406 pages
...triangles, is equal to two right angles (th. 17); therefore 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, which are so many many of the angles of the triangles,...

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

Euclides - 1816 - 588 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...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, by...

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

John Playfair - 1819 - 354 pages
...have any number of sides, the proposition is demonstrated just as in the case of a triangle. Therefore all the exterior angles of any rectilineal figure are together equal to four right angles. QED COR. 1. Hence, all the interior angles of any triangle are equal to two right angles. For all the...

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

John Playfair - Circle-squaring - 1819 - 350 pages
...angles as there are triangles (32. 1.) ; that is, as there are sides in the figure BCDEF ; and because all the angles of the figure, together with four right angles, are likewise equal to twice as many right angles as there are sides in the figure (cor. 1. 32. 1.) ; therefore...

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

Euclid, Robert Simson - Geometry - 1821 - 514 pages
...angles. Wherefore if a side of a triangle, &c. QED COK. 1. All the interior aigles of any rectilineal figure, together with four right angles, are equal to twice as many right E' angles as the figure has sides. For any rectilineal figure ABCDE can be divided into as many triangles...

## The First Six Books with Notes

Euclid - 1822 - 222 pages
...therefore equal to B AE and EAC. Cor. 6. All the internal angles of any rectilineal figure, ABCDE, together with four right angles, are equal to twice as many right angles as the figure has sides. Take any point F within the figure and draw the right lines FA, FB, FC, FD, and FE. There are formed...

## Euclid's Elements of Geometry: The Six First Books. To which are Added ...

Rev. John Allen - Astronomy - 1822 - 508 pages
...as many right angles, except four, as the figure has sides ; and all tbe angles of these triangles are equal to twice as many right angles as the figure has sides (32. 1 /CM.), therefore the angles of these triangles which are at their common vertex A, being those...

## A Course of Mathematics: For the Use of Academies, as Well as Private ...

Charles Hutton - Mathematics - 1822 - 616 pages
...triangles, is equal to two right angles (th. 17) ; therefore 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, which are so / many of the angles of the triangles,...