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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.
Elementary Geometry: With Applications in Mensuration - Page 33
by Charles Davies - 1850 - 216 pages

## Elementary Course of Geometry ...

Charles William Hackley - Geometry - 1847 - 248 pages
...sum. Hence it follows that the sum of all the inward angles of the polygon alone, A + B -f- C + D + E, is equal to twice as many right angles as the figure has sides, wanting the said four right angles. QED Corol. 1. In any quadrangle, the sum of all the four inward...

## The English Journal of Education, Volume 1

Education - 1847 - 508 pages
...SECTION I. — 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. 2. Equal triangles, upon equal bases in the same straight line, and towards the same parts, are between...

## The definitions, postulates, axioms, and enunciations of the propositions of ...

Euclides - 1848 - 52 pages
...angles. 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. COB. 2. All the exterior angles of any rectilineal figure, made by producing the sides successively...

## Elements of Geometry and Conic Sections

Elias Loomis - Conic sections - 1849 - 252 pages
...has sides. angles of each of these triangles, is equal to two right angles (Prop. XXVII.); therefore the sum of the angles of all the triangles, is equal to twice as many right angles as the polygon has sides. But the same angles are equal to the angles of the polygon, together with the angles...

## Elements of Geometry and Trigonometry Translated from the French of A.M ...

Charles Davies - Trigonometry - 1849 - 372 pages
...equal to two right angles, taken as many times, less two, as the polygon has sides (Prop. XXVI.); that is, equal to twice as many right angles as the figure has sides, wanting four right angles. Hence, the interior angles plus four right Let the sides of the polygon...

## The first three books of Euclid's Elements of geometry, with theorems and ...

Euclid, Thomas Tate - 1849 - 120 pages
...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 ABODE can be divided into as many triangles as the figure has sides, by...

## A Rudimentary Treatise on Land and Enigineering Surveying with All the ...

Thomas Baker - Railroads - 1850 - 244 pages
...taking the angles or measuring the lines. But since the sum of all the interior angles of a polygon is equal to twice as many right angles as the figure has sides, lessened by four right angles, and since the given figure has five sides, the sum of all its five interior...

## The Church of England quarterly review, Volume 28

1850 - 524 pages
...proposition that all the interior angles of any rectilinear figure, together with four right angles, are equal to twice as many right angles as the figure has sides : and the dictum is equally true, too, in moral science — only in any particular case to dogmatize...