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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

## Examination papers, and division lists, &c. [afterw.] General certificate of ...

Oxford univ, local exams - 1880 - 396 pages
...explain what you mean by a straight line touching a circle, and by a straight line placed in a circle. 2. All the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides. 3. If the square described on one side of a triangle be equal to the squares described on the other...

## An elementary treatise on geometrical drawing

John Henry Robson - 1880 - 116 pages
...problem is the sth Proposition of Euclid's Fourth Book. 12. By Euc. I. 32, Cor. 1, it is proved that " All the Interior angles of any Rectilineal figure,..."twice as many right angles as the figure has " sides." If, therefore, we suppose the polygon to have n sides, All its interior angles + 4.90 .= 272.90 . -....

## (Report).

Elizabethan club - 1880 - 156 pages
...of the acute angles at the other point, and similarly of the obtuse angles. 3. All the angles of a rectilineal figure, together with four right angles,...twice as many right angles as the figure has sides. A floor has to be laid with tiles in the form of regular figures all equal and similar ; show what...

## Nature, Volume 21

Sir Norman Lockyer - Electronic journals - 1880 - 668 pages
...the flat angle we may take Theorem XXVI. of the syllabus, that the interior angles of any polygon, together with four right angles, are equal to twice as many right angles as the figure has sides. In the new notation we would say that the sum of the interior angles of the polygon is equal to a number...

## Elements of Geometry, Conic Sections, and Plane Trigonometry

Elias Loomis - Conic sections - 1880 - 452 pages
...is the complement of the other. PROPOSITION XXVIII. THEOREM. All the interior angles of a polygon, together with four right angles, are equal to twice as many right angles as the figure IMS sides. Let ABCDE be any polygon ; then all its interior angles A, B, C, D, E, together with four...

## An Elementary Geometry: Plane, Solid and Spherical

William Frothingham Bradbury - Geometry - 1880 - 260 pages
...minus two. Let ABCDEF be the given polygon ; the sum of all the interior angles A, B, C, D, E, F, is equal to twice as many right angles as the figure has sides minus two. For if from any vertex A, diagonals AC, AD, AE, are drawn, the polygon will be divided into...

## A Treatise on Land-surveying: Comprising the Theory Developed from Five ...

William Mitchell Gillespie - Surveying - 1880 - 540 pages
...proposition of Geometry, that in any figure bounded by straight lines, the sum of all the interior angles is equal to twice as many right angles, as the figure has sides less two ; since the figure can be divided into that number of triangles. Hence this common rule. "...

## The Elements of geometry; or, The first six books, with the eleventh and ...

Euclides - Euclid's Elements - 1881 - 236 pages
...ACB are equal (Ax. 1) to two right angles. Wherefore, if a side of any triangle be produced, &c. a ED COR. 1. — All the interior angles of any rectilineal...twice as many right angles as the figure has sides. Let ABCDE be any rectilineal figure. All the interior angles ABC, BCD, &c. together with four right...