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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 Geometry: Containing the First Six Books of Euclid, with a ... - Page 294
by Euclid, John Playfair - 1846 - 317 pages

## Hints to Travellers: Scientific and General, Volume 1

Royal Geographical Society (Great Britain) - Scientific expeditions - 1906 - 512 pages
...together with the line AB form an enclosed figure, then the sum of all the interior angles should be equal to twice as many right angles as the figure has sides, less four right angles. We thus have a check on the observed horizontal angles. It should be carefully...

## A School Geometry, Parts 1-4

Henry Sinclair Hall - 1908 - 286 pages
...GEOMETRY. COROLLARY 1. ^M <Ae interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides. Let ABCDE be a rectilineal figure of & sides. It is required to prove that all the interior angles...

## Intermediate Geometry: Being Sections V and VI of "geometry, Theoretical and ...

Walter Percy Workman - Geometry - 1908 - 228 pages
...angles ; and in any convex polygon the sum of the interior angles, together with four right angles, is equal to twice as many right angles as the figure has sides (Euc. I. 32, Cor.) 110 Congruence. CI — If two triangles have two sides and the included angle in...

## Introduction and books 1,2

Euclid - Mathematics, Greek - 1908 - 550 pages
...somewhat simpler than, Simson's. 1. The sum of the interior angles of a convex rectilineal figure is equal to twice as many right angles as the figure has sides, less four. For let one angular point A be joined to all the other angular points with which it is not...

## Practical Calculations for Engineers: For the Use of Engineering Students ...

Charles E. Larard, Henry A. Golding - Engineering - 1909 - 558 pages
...angles. = 180' (fig. 2). FIG. 1. FIG. 2. The sum of the interior angles of any rectilineal figure is equal to twice as many right angles as the figure has sides, less 4. Thus, for example, in the irregular pentagon (fig. 3), = 2 x 5 x 90° - 4 x 90° ; FIG. 3....

## College Entrance Examination Papers in Plane Geometry

Geometry, Plane - 1911 - 192 pages
...whose altitude is 3 inches. SEPTEMBER, 1909 1. The sum of all the interior angles of any polygon is equal to twice as many right angles as the figure has sides, less four right angles. 2. The angle between two chords which intersect within a circle is measured...

## Special Reports on Educational Subjects, Volumes 26-27

Great Britain. Board of Education - Education - 1912 - 1048 pages
...half BC. 2. Prove that 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. Find the number of sides of a regular polygon, each angle of which is equal to the sum of an angle...

## Annual Report of the Department of Education ..., Volume 4, Part 1911; Volume 6

Alberta. Department of Education - Education - 1912 - 244 pages
...28—1. 6 8. Prove that 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. 8 9. (a) If a straight line be bisected and produced to any point, the rectangle contained by the whole...