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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.
The synoptical Euclid; being the first four books of Euclid's Elements of ... - Page 32
by Euclides - 1853

## The Elements of Euclid [book 1] for beginners, by J. Lowres

Euclides - 1852 - 48 pages
...produced be equal to the base, and joining the end of the produced line to the end of the base. COB. 3. All the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides. COB. 4. All the exterior angles of any rectilineal figure are together equal to four right angles....

## The first two books of the Elements of Euclid, with additional figures ...

Euclides - 1852 - 152 pages
...that is a , together with four right angles. . 2 Cor Therefore all the angles of the figure, XT - *• together with four right angles, are equal to twice as many right angles as the figure has sides. [The triangle furnishes an instance of this, for all its angles are together equal to two right angles;...

## The English Journal of Education, Volume 6

Education - 1852 - 512 pages
...EUCLID. SECTION I. — 1. The angles at the base of an isosceles triangle are equal to each other. 2. All the interior angles of any rectilineal figure,...together with four right angles, are equal to twice us many right angles as the figure has sides. 3. To a given straight line to apply a parallelogram...

## Elements of Geometry and Trigonometry

Adrien Marie Legendre - Geometry - 1852 - 436 pages
...triangles in the figure ; that is, as many times as there are sides, less two. But this product is equal to twice as many right angles as the figure has sides, less four right angles. Cor. 1. The sum of the interior angles in a quadrilateral, is equal to two...

## Elements of Geometry and Trigonometry: With Applications in Mensuration

Charles Davies - Geometry - 1886 - 340 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. 4) ; and...

## The geometry, by T. S. Davies. Conic sections, by Stephen Fenwick

Royal Military Academy, Woolwich - Mathematics - 1853 - 400 pages
...angles CBA, BAC, ACB, are equal to two right angles. Wherefore, if a side of a triangle, etc. QED COR. 1. All the interior angles of any rectilineal figure,...with four right angles, are equal to twice as many D right angles as the figure has sides. E.«=^lT"\~~-^, \ 4C-\ For any rectilineal figure ABCDE can...

## The first six books of the Elements of Euclid, with numerous exercises

Euclides - Geometry - 1853 - 176 pages
...triangles : that is (i. 15, cor. 2), together with four right angles. Therefore all the angles of the figure, together with four right angles, are equal...twice as many right angles as the figure has sides. Сод. 2. All the exterior angles of any rectilineal figure are together equal to four right ,ingles....

## The Elements of Euclid: With Many Additional Propositions ..., Part 1

Euclid - Geometry - 1853 - 176 pages
...internal angles, are equal to twice as many right angles as the figure has sides; but the internal angles, together with four right angles, are equal to twice as many right angles as the figure has sides (6); take away from both the internal angles, and the external angles remain, equal to four right angles...

## The Elements of Euclid, books i-vi; xi. 1-21; xii. 1,2; ed. by H.J. Hose, Book 1

Euclides - Geometry - 1853 - 334 pages
...the angles of the polygon together with four right angles. But all the angles of the polygon GHKLM together with four right angles are equal to twice as many right angles as the polygon has sides (i. 32. Cor. i), that is, as there are plane angles constituting the solid angle...

## Orr's Circle of the Sciences: Organic nature, vols. 1-3 (1854-1856)

William Somerville Orr - Science - 1854 - 534 pages
...the three angles of the triangle are = two right angles, .'. if a side of a triangle, &c. QED Сов. 1. — All the interior angles of any rectilineal figure, together with four right angles, are = twice as many right angles as the figure has sides. For, any rectilineal figure ABODE can be divided...