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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 sidef. For any rectilineal figure ABCDE can be divided into as many triangles as the figure has sides, by drawing...
Elements of geometry: consisting of the first four,and the sixth, books of ... - Page 30
by Euclides - 1842

## The Elements of Surveying and Geodesy

William Charles Popplewell - Geodesy - 1915 - 268 pages
...Stated precisely, " the sum of all the internal angles of a closed polygon plus four right angles is equal to twice as many right angles as the figure has sides." So that it is easy from the field notes to find the internal angle at each corner of the figure, and...

## Surveying as Practised by Civil Engineers and Surveyors: Including the ...

John Whitelaw - Surveying - 1916 - 578 pages
...measurements before leaving the ground, as " the sum of the interior angles of any rectilinear figure is equal to twice as many right angles as the figure has sides, less four right angles." In the case of Fig. 73, as the figure is four-sided the sum of the interior...

## The Founder's Manual: A Presentation of Modern Foundry Operations, for the ...

David Wells Payne - Founding - 1917 - 724 pages
...to corresponding angles are proportional. (6) In any polygon, the sum of all the interior angles is equal to twice as many right angles as the figure has sides, less four right angles. (7) In any polygon the sum of all the exterior angles is equal to four right...

## A Text-book of Theodolite Surveying and Levelling: For the Use of Students ...

James Park - Azimuth - 1922 - 598 pages
...iii . . . . 141 12 iv .... 66 40 Total . 360° 00' And the sum of the internal angles of a polygon is equal to twice as many right angles as the figure has sides, less four right angles. Our figure has four sides, .-. 90(4x2) -(4x90) =360°, which agrees with the...

## Surveying as Practised by Civil Engineers and Surveyors, Including the ...

John Whitelaw - Surveying - 1924 - 650 pages
...measurements before leaving the ground, as " the sum of the interior angles of any rectilinear figure is equal to twice as many right angles as the figure has sides, less four right angles." In the case of Fig. 73, as the figure is four-sided the sum of the interior...