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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.
Elements of Plane Geometry - Page 46
by Thomas Hunter - 1878 - 132 pages

## Elements of Geometry...: Translated from the French for the Use of the ...

Adrien Marie Legendre, John Farrar - Geometry - 1825 - 280 pages
...part BAE is equal to the angle B, and the other part DAE is equal to the angle C (67). THEOREM. 79. The sum of all the interior angles of a polygon is equal to as 4 many times two right angles as there are units in the number of sides minus two. Demonstration....

## Elements of Geometry...: Translated from the French for the Use of the ...

Adrien Marie Legendre, John Farrar - Geometry - 1825 - 294 pages
...to the angle Z?, and the other part DAE is equal to the angle C (67). . J c/ .\ THEOREM. . X ^ 79. The sum of all the interior angles of a polygon is equal to as many times two right angles as there are units in the number of sides minus two. Demonstration....

## Elements of Geometry

Adrien Marie Legendre - 1825 - 570 pages
...part BAE is equal to the angk B, and the other part DAE is equal to the angle C (67). THEOREM. 79. The sum of all the interior angles of a polygon is equal to as many times two right angles as there are units in the number of sides minus two. Demonstration....

## A Popular Course of Pure and Mixed Mathematics ...: With Tables of ...

Peter Nicholson - Mathematics - 1825 - 1046 pages
...I). Cor. 1 . All the interior angles of any rectilínea] 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, by...

## Elements of Arithmetic, Algebra, and Geometry

George Lees - 1826 - 266 pages
...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. PROP. XIII. THEOREM. If two triangles, BAG, EOF, have two angles, BAG, ABC, and a side...

## Elements of Geometry: With Notes

John Radford Young - Euclid's Elements - 1827 - 246 pages
...in each triangle amounts to two right angles, therefore the angles of all the triangles are together equal to twice as many right angles as the figure has sides, that is to say, the sum of the angles of the polygon, together with those about the point within it,...

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

Robert Simson - Trigonometry - 1827 - 546 pages
...zi. 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, by...

## The First Six Books of the Elements of Euclid, with a Commentary and ...

Euclid, Dionysius Lardner - Euclid's Elements - 1828 - 544 pages
...Hence it follows, that the sum of all the angles internal and external, including the reentrant angles, is equal to twice as many right angles as the figure has sides, together with the excess of every reentrant angle above two right angles. But (134) the sum of the...