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 papers set at the professional preliminary examination - Page 10
by College of preceptors - 1882

## 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
...angles CBA, BAC, ACB, are equal to two right angles. Wherefore if a side of a triangle, &c. QED COR. 1. All the interior angles of any rectilineal figure,...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 - Circle-squaring - 1819 - 333 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 tegether equal to four...

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

Euclid, Robert Simson - Geometry - 1821 - 516 pages
...equal to two right 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 - 179 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 - Geometry - 1822 - 494 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
...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,...

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

Euclid, Rev. John Allen - Astronomy - 1822 - 494 pages
...two right angles [13. 1} ; therefore all the exterior and interior angles of the figure are together equal to twice as many right angles as the figure has sides ; but the interior angles are equal to twice as many right angles, except four, as the figure has sides...