Books Books
... together with four right angles, are equal to twice as many right angles as the figure has sides.
Elements of geometry, based on Euclid, book i - Page 41
by Edward Atkins - 1877

The Young Surveyor's Guide: Or, A New Introduction to the Whole Art of ...

Edward Laurence - Surveying - 1716 - 408 pages
...external < a, is equal to t wo right Angles (by tbe^tb /)confequently all the internal and external Angles are equal to twice as many right Angles as the Figure has fides. But all its internal Angles are equal to twiee as many right Angles eicept 4 as it has fides...

The Young Gentleman's Arithmetick, and Geometry: Containing Such Elements of ...

Edward Wells - Arithmetic - 1723 - 358 pages
...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 Corol....

Euclid's Elements of Geometry: From the Latin Translation of Commandine. To ...

John Keill - Logarithms - 1723 - 444 pages
...Angles of alt the Triangles are equal to the inward Angles of the Fii gure. Therefore all the inward Angles of the Figure are equal to twice as many Right Angles as there art Triangles, that is, twice as many Rirot Angles, taking away four, as the Figure has Sides....

Euclid's Elements of Geometry,: From the Latin Translation of Commandine. To ...

Euclid, John Keill - Geometry - 1733 - 444 pages
...Angles of all the Triangles are equal to the inward Angles of the Figure. Therefore all the inward Angles of the Figure are equal to twice as many Right Angles as there are Triangles, that is, twice as many Right Angles, taking nuayfour, as the, Figure has Sides....

The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1762 - 488 pages
...every interior angle ABC with it's adjacent exterior *, ' 5- 1. ABD is equal b to two right angles; therefore all the interior together with all the exterior...figure, are equal to twice as many right angles as there are fides of the figure, that Is, by the foregoing Corollary, they are equal to all the interior...

Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books

Euclid - Geometry - 1765 - 492 pages
...triangles are equal to ail the inward angles of the tiirht-lined figure ; therefore all the inward angles of the figure are equal to twice as many right angles as there are triangles ; that is, equal to twice as many right angles, wanting the angles of two triangles...

A Royal Road to Geometry: Or, an Easy and Familiar Introduction to the ...

Thomas Malton - 1774 - 484 pages
...fubtended by 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...

The Elements of Euclid, Viz: The Errors, by which Theon, Or Others, Have ...

Robert Simson - Trigonometry - 1775 - 534 pages
...every interior angle ABC,'with its adjacent exterior b i3. i. ABD, is equal b to two right angles; therefore all the interior, together with all the...figure, are equal to twice as many right angles as there are fides of the figure; that is, by the foregoing corollary, they are equal to all the interior...