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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.
Euclid's Elements [book 1-6] with corrections, by J.R. Young - Page 41
by Euclides - 1838

## Minutes of the Committee of Council on Education, with Appendices, Volume 2

...thickness. GEOMETRY AND TRIGONOMETRY. (One Question is only to be answered in each Section.) Section I. 1. All the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides. 2. If the square described upon one side of a triangle be equal to the sum of the squares described...

## The Church of England quarterly review, Volume 28

1850
...revelation could supersede the reasoning of the proposition that all the interior angles of any rectilinear figure, together with four right angles, are equal...twice as many right angles as the figure has sides : and the dictum is equally true, too, in moral science — only in any particular case to dogmatize...

## Elementary Geometry: With Applications in Mensuration

Charles Davies - Geometry - 1850 - 216 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...

## ELEMENTARY GEOMETRY, WITH APPLICATIONS IN MENSURATION.

CHARLES DAVIS, L.L. D. - 1850
...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...

## Plane trigonometry. [With] Solutions of examples. Appendix &c., to adapt the ...

...such cases, where very great accuracy is not required. 16. It appears, from Eue. i. 32, Cor. 1, that ' all the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides.' Hence if и be the number of sides of any rectilineal figure, we have the sum of its n angles + 4 x...

## The English Journal of Education, Volume 5

Education - 1851
...three pickmen to every two shovellers, and to each workman 2s. 6d. per day. EUCLID. SECTION I.—1. All the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides. SECTION II. — I. If a straight line drawn through the centre of a circle cuts another at right angles...

## A Manual of Surveying for India, Detailing the Mode of Operations on the ...

Sir Henry Edward Landor Thuillier - Surveying - 1851 - 718 pages
...passing through the other end. In the 3rd Cor. Theor. V., (page 12,) it is stated and proved, " that all the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides" or in other words that — In any rectilineal figure, the sum of all the interior angles, is equal...

## An Epitome of Navigation and Nautical Astronomy, with Improved Lunar Tables ...

Janet Taylor - Nautical astronomy - 1851 - 621 pages
...being the two angles made by cne line meeting another. The sum of all the outward and inward angles, is equal to twice as many right angles as the figure has sides; but the sum of all the inward angles is equal to twice as man1 right angles as the figure has sides,...