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 of plane geometry [book 1-6] explicitly enunciated, by J ... - Page 55
by Euclides - 1860 ## The Young Gentleman's Arithmetick, and Geometry: Containing Such Elements of ...

Edward Wells - Arithmetic - 1714 - 292 pages
...th«i Sum of all the Angles in all the Tri* angles, into which the Figure is divided, will together be equal to twice as many right Angles, as the Figure has Sidesj But the Angles about P, the inward Point of each Figure, wherein all fhe Triangles concur, are... ## The Young Gentleman's Arithmetick, and Geometry: Containing Such Elements of ...

Edward Wells - Arithmetic - 1723 - 294 pages
...Right-, the Sum of all the Angles in all the Tri~ angles, into which the Figure is divided, will together be equal to twice as ma-ny right Angles, as the Figure has Sides. But the Angles about P, the inward Point of each Figure, wherein all the Triangles concur, are (by... ## Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books

Euclid - Geometry - 1765 - 464 pages
...is, has fides. But fince all the inward angles together, with four right angles, has been proved to be equal to twice as many right angles as the figure has fides ; therefore all the inward angles, together with four right angles, is equal to all the inward... ## A Royal Road to Geometry: Or, an Easy and Familiar Introduction to the ...

Thomas Malton - 1774 - 482 pages
...the Sides. ie equal to four Right Angles. And, all the internal Angles of any Right-lined Figure are equal to twice as many Right Angles as the Figure has Sides, wanting four, (Th. i. i0. i.) confequently, the external Angles being equal to thofe four (Th. 2. of... ## A Treatise on Mensuration, Both in Theory and Practice

Charles Hutton - Measurement - 1788 - 728 pages
...prove the work ; add all the inward angles A, B, c, &c, together, and when the work is right, their fum will be equal to twice as many right angles as the figure has fides, wanting 4 right angles. And when there is an angle, as F, that bends inwards, and you meafure... ## Mathematics: Compiled from the Best Authors and Intended to be the ..., Volume 2

Mathematics - 1801 - 658 pages
...the work ;• add all the inward angles A, B, C, &c. together, and when the work is right, their sum will be equal to twice as many right angles, as the figure has sides, wanting four right angles. And when there is an angle, as F, that bends inward, and you measure the... ## The Accomplished Tutor; Or, Complete System of Liberal Education ..., Volume 1

Thomas Hodson - Arithmetic - 1806 - 492 pages
...prove the work ; — add all the inward angles ABC, &c. together ; and if the work be right, the fum will be equal to twice as many right angles as the figure has fides, except four right angles ; but when there is an angle that bends inwards, as at F, and you meafure... ## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - Euclid's Elements - 1806 - 320 pages
...if a side of a triangle, &c. QED "7^ COR. 1. All the interior angles of any rectilineal figure are equal to twice as many right angles as the figure has sides, wanting four right angles. For any rectilineal figure ABCDE can be divided into as many triangles as... ## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1806 - 518 pages
...D, CoR. 1 . 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. For any rectilineal figure ABCDE can be divided into as many triangles as the figure has sides, by... 