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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

## Elementary Course of Geometry ...

Charles William Hackley - Geometry - 1847 - 248 pages
...being equal to the same in another, the triangles are equal. THEOREM XVI. The sum of all the inward angles of a polygon is equal to twice as many right angles, wanting four, as the figure has sides. Let ABODE be any figure ; then the sum of all its inward angles,...

## 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 ...

Euclid - 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
...angles is one third of two right angles, or two thirds of one right angle. PROPOSITION XXVIII. THEOREM. The sum of all the interior angles of a polygon, is equal to twice as many right angles, wanting four, as the figure has sides. angles of each of these triangles, is equal to two right angles...

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

Charles Davies - Trigonometry - 1849 - 384 pages
...is equal to the angle B, and the other part DAE is equal to the angle C. PROPOSITION XXVI. THEOREM. The sum of all the interior angles of a polygon, is equal to two right angles, taken as many times less two, as the figure has sides. Let ABCDEFG be the pioposed...

## 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 Engineering Surveying: With All the ...

Thomas Baker - Railroads - 1850 - 244 pages
...considerable distance, there has been an error either in taking the angles or measuring the lines. But since the sum of all the interior angles of a polygon is...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...

## Elementary Geometry: With Applications in Mensuration

Charles Davies - Geometry - 1850 - 218 pages
...triangles is equal to two right angles (Th. xvii) : hence, 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 is equal to four right angles (Th. ii. Cor. 3) ; and...