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. Euclid's Elements [book 1-6] with corrections, by J.R. Young - Page 41
by Euclides - 1838 ## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

Euclid, John Playfair - Euclid's Elements - 1846 - 332 pages
...as the figure has sides ; but the exterior are equal to four right angles ; therefore the interior are equal to twice as many right angles as the figure has sides, wanting four. PROP. II. Two straight lines, which make with a third line the interior angles on the... ## The English Journal of Education, Volume 1

Education - 1847 - 508 pages
...liquidation of it. In how many years will the debt be paid off? OEOMETBY AND TRIGOSO1IETBY. SECTION I. — 1. All the interior angles of any rectilineal figure,...twice as many right angles as the figure has sides. 2. Equal triangles, upon equal bases in the same straight line, and towards the same parts, are between... ## Minutes of the Committee of Council on Education, Volume 1

...liquidation of it. In how many years will the debt be paid off? GEOMETRY AND TRIGONOMETRY. SECTION I. 1. All the interior angles of any rectilineal figure,...equal to twice as many right angles as the figure hag sides. 2. Equal triangles, upon equal bases in the same straight line, and towards the same parts,... ## A Complete Treatise on Practical Land-surveying: In All Its Departments ...

Anthony Nesbit - Plane trigonometry - 1847 - 426 pages
...accuracy of the previous work. Moreover, since the sum of all the interior angles of any polygon is equal to twice as many right angles as the figure has sides, lessened by four ; as the given figure has five sides, the sum of all its interior angles must be 2x5... ## Elementary Course of Geometry ...

Charles William Hackley - Geometry - 1847 - 248 pages
...Hence it follows that the sum of all the inward angles of the polygon alone, A + B -f- C + D + E, is equal to twice as many right angles as the figure has sides, wanting the said four right angles. QED Corol. 1. In any quadrangle, the sum of all the four inward... ## The definitions, postulates, axioms, and enunciations of the propositions of ...

Euclides - 1848 - 52 pages
...angles ; and the three ulterior angles of every triangle are together equal to two right angles. COR. 1. All the interior angles of any rectilineal figure...twice as many right angles as the figure has sides. COB. 2. All the exterior angles of any rectilineal figure, made by producing the sides successively... ## The first three books of Euclid's Elements of geometry, with theorems and ...

Euclid, Thomas Tate - 1849 - 120 pages
...triangles ; that is (Cor. 2. i. 15.), 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. COR. 2. All the exterior angles of any rectilineal figuro, are together equal to four right angles.... ## Elements of Geometry and Conic Sections

Elias Loomis - Conic sections - 1849 - 252 pages
...(Prop. XXVII., BI), that is, as there are sides of the polygon BCDEF. Also, the angles of the polygon, together with four right angles, are equal to twice as many right angles as the figure has sides (Prop. XXVIII., BI); hence all the angles of the triangles are equal to all the angles of the polygon,... ## Elements of Geometry and Trigonometry Translated from the French of A.M ...

Charles Davies - Trigonometry - 1849 - 384 pages
...to two right angles, taken as many times, less two, as the polygon has sides (Prop. XXVI.); that is, equal to twice as many right angles as the figure has sides, wanting four right angles. Hence, the interior angles plus four right Let the sides of the polygon... 