Books Books 1 - 10 of 79 on In any triangle, the sum of the three angles is equal to two right angles, or 180°..
In any triangle, the sum of the three angles is equal to two right angles, or 180°.
American Practical Navigator - Page 6
1821

## Elements of Plane and Spherical Trigonometry: With Their Applications to ...

Olinthus Gregory - Plane trigonometry - 1816 - 244 pages
...• — -', it will become gin c = sin A cos H + sin it cos A, Now, since in every plane triangle, the sum of the three angles is equal to two right angles, A + B = supplement of c ; and, since an angle and its supplement have the same sine, it follows that...

## Elements of Geometry

Adrien Marie Legendre - Geometry - 1819 - 208 pages
...case the angle DEH and the angle BAC would together make two right angles. THEOREM. In. every triangle the sum of the three angles is equal to two right angles. , 41. Demonstration. Let ABC (Jig. 41) be any triangle; produce the side CA toward D, and draw to the...

## Elements of Geometry and Trigonometry: With Notes

Adrien Marie Legendre - Geometry - 1822 - 367 pages
...Note II. of his Geometry, gives of the fundamental proposition, that, in every rectilineal triangle, the sum of the three angles is equal to two right angles. This demonstration is the more remarkable, as it makes no use of the theory of parallels, but, on the...

## Description and Use of a Diagram of Navigation: By which All Problems in ...

George Watson (of Belfast, Maine.) - Navigation - 1822 - 64 pages
...sides. 196. The longest side bf any triangle is opposite the greatest angle. 195. In all plane triangles the sum of the three angles is equal to two right angles, or 180 deg. 198. An angle in a segment less than a semicircle is greater than a right angle. 197. An...

## Elements of Geometry...: Translated from the French for the Use of the ...

Adrien Marie Legendre - Geometry - 1825 - 224 pages
...DEH and the angle BAC would together make two right angles. 27 THEOREM. A. ' 72. In every triangle the sum of the three angles 'is equal to two right angles. Pig. 41. Demonstration. Let ABC (fig. 41) be any triangle ; produce the side CA toward D, and draw...

## The New American Practical Navigator: Being an Epitome of Navigation ...

Nathaniel Bowditch - Nautical astronomy - 1826 - 617 pages
...to the sum of the two angles EFG and EGF, and at the same time equal to EFG alone, which is ahsurd ; therefore the lines AB, CD cannot meet« and must...triangle ABC, the sum of the three angles is equal lo iico right angles. To prove this, you must produce BC (in the Jig. art. Sä,) towards D, then (by...

## The New American Practical Navigator: Being an Epitome of Navigation ...

Nathaniel Bowditch - Nautical astronomy - 1826 - 617 pages
...equal to the sum of the two angles EFG and EGF, and at the same time equal to EFG alone, whicl: surd ; therefore the lines AB, CD cannot meet, and must be parallel. XXXV. Ill any right lined triangle ABC, the sum of the three angles is equal right angles. To prove this,...

## Elements of Geometry: With Notes

John Radford Young - Geometry, Plane - 1827 - 208 pages
...Cor. 1. Since the angle ACD together with ACB make two right angles, it follows that in every triangle the sum of the three angles is equal to two right angles. Cor. 2. Hence if two angles in one triangle be equal to two in another, the third angle in the one...