Books Books 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: For the Use of Schools - Page 81
by Nicholas Tillinghast - 1844 - 96 pages ## Text Book of Topographical and Geographical Surveying

C. F. Close - Surveying - 1905 - 376 pages
...together with the line AB form an enclosed figure, and 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 noted that the included... ## A text-book of engineering drawing and design

Sidney Herbert Wells - Machine design - 1905 - 246 pages
...which says, that " the interior angles of any straight lined figure together with four right angles are equal to twice as many right angles as the figure has sides." The most common of the regular polygons used in engineering designs are the pentagon (five-sided),... ## 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 noted that the included... ## Annual Report - Dept. of Education

Saskatchewan. Department of Education - Education - 1906 - 188 pages
...? Show 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. (c) Derive the magnitude of an angle of a regular octagon. (d) If the exterior vertical angle of an... ## Introduction and books 1,2

Euclid - Mathematics, Greek - 1908 - 550 pages
...perhaps 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 connected... ## 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... ## Books 10-13 and appendix

Euclid - Mathematics, Greek - 1908 - 576 pages
...assume the proposition that the interior angles of a convex polygon together with four right angles are equal to twice as many right angles as the figure has sides. Let there be any convex polyhedral angle with V as vertex, and let it be cut by any plane meeting its... ## A School Geometry, Parts 1-4

Henry Sinclair Hall - 1908 - 286 pages
...42 COR. 1. All the interior angles of any rectilineal figure, 2 together with four right angles, are equal to twice as many right angles as the figure has sides. 44 COR. 2. If the sides of a rectilineal figure, which has no re-entrant angle, are produced in order,... ## Practical Calculations for Engineers, for the Use of Engineering Students ...

Charles Edward Larard, Henry Albert Golding - Engineering - 1909 - 506 pages
...to two right angles. 0- (fig. 2). Fm. 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. or generally,... 