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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.
A Course of Mathematics: For the Use of Academies as Well as Private Tuition ... - Page 292
by Charles Hutton - 1831

## The Cambridge Examiner, Volume 2

Education, Higher - 1882 - 498 pages
...every respect. 4 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. 5. Equal triangles upon equal bases in the same straight line and towards the same parts are between...

## Class lessons on Euclid

Marianne Nops - 1882 - 278 pages
...these vertical angles and we have remaining the interior angles of the figure, which will clearly be equal to twice as many right angles as the figure has sides, less four right angles. IV. If we produce all the sides of this figure, we shall have an exterior angle...

## The Competitor, Volumes 1-2

1882 - 480 pages
...EXPLANATIONS. 1. All the internal angles of any convex rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides (Euclid I., 32 Cor.) n denoting the number of sides : and T two right angles. (n — 2) T = angles...

## Geometry for schools, comprising books i. and ii. of Euclid, with some ...

Euclides - 1883 - 176 pages
...the base and from one another. COB. l.— The sum of the interior angles of any rectilineal figure is equal to twice as many right angles as the figure has sides, minus four right angles. Take any rectilineal figure, as ABCDEF, and take G, any point within it. Join...

## Essentials of Geometry

Alfred Hix Welsh - Geometry - 1883 - 326 pages
...Th. XXIV. Therefore, if, etc. QUERY. THEOREM XXVI. The sum of the interior angles of a polygon, plus four right angles, is equal to twice as many right angles as the polygon has sides. For, take any polygon, as ABCD E. If from any point within it, as F, lines be drawn...

## The Elements of Euclid for the Use of Schools and Colleges: Comprising the ...

Euclid, Isaac Todhunter - Euclid's Elements - 1883 - 426 pages
...Corollary 2. Therefore all the interior angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. COROLLARY 2. All the exterior angles of any rectilineal figure are together equal to four right angles....

## The Practical Teacher; with which is Incorporated the Practical ..., Volume 2

Joseph Hughes - Education - 1883 - 578 pages
...be used.] 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. See Corollary to Euclid I. 32. If the figure be equiangular and four interior angles be equal to seven...

## The Practical Teacher, Volume 2

Education - 1883 - 658 pages
...be used.] 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. See Corollary to Euclid I. 32. If the figure be equiangular and four interior angles be e ]ual to seven...