Books Books
... the three angles of a triangle are together equal to two right angles, although it is not known to all.
The Works of John Playfair ...: With a Memoir of the Author ... - Page 335
by John Playfair - 1822

## The questions set at the matriculation examination of the London university ...

Walter Percy Workman - 1880 - 248 pages
...the angle BFA is equal to the difference between two right angles and twice the angle ACB ; because the three angles of a triangle are together equal to two right angles. [i. 32. By precisely similar reasoning it may be shown that AEC is equal to the difference between...

## The Elements of Euclid for the Use of Schools and Colleges: With Notes, an ...

Isaac Todhunter - 1880 - 426 pages
...equilateral ; therefore the three angles EGD, GDE, DEG are equal to one another. [I. 5. Corollary. But the three angles of a triangle are together equal to two right angles; [I. 32. therefore the angle EGD is the third part of two right [Axiom 1. In the samp manner it may...

## Practical plane geometry and projection. [2 issues].

Henry Angel - 1880 - 360 pages
...When it equals that angle, the plane containing them is perpendicular to the hp This is obvious, as the three angles of a triangle are together equal to two right angles, and the lines have their greatest inclinations when they are contained by a vertical plane. The angle...

## Practical Plane Geometry and Projection: For Science Classes ..., Volume 1

Henry Angel - 1880 - 362 pages
...When it equals that angle, the plane containing them is perpendicular to the hp This is obvious, as the three angles of a triangle are together equal to two right angles, and the lines have their greatest inclinations when they are contained by a vertical plane. The angle...

## The Doctrine of Germs, Or, The Integration of Certain Partial Differential ...

Samuel Earnshaw - 1881 - 602 pages
...we shall see that the further progress of mathematics was indirectly to a very great extent due. b. The three angles of a triangle are together equal to two right angles. Eudemus, according to a statement of Proclus on Euclid i. 32, ascribes the discovery of this theorem...

## An Introduction to the Ancient and Modern Geometry of Conics: Being a ...

Charles Taylor - 1881 - 512 pages
...we shall see that the further progress of mathematics was indirectly to a very great extent due. i. The three angles of a triangle are together equal to two right angles. Eudemus, according to a statement of Proclus on Euclid I. 32, ascribes the discovery of this theorem...

## A Treatise on Marine Surveying: Prepared for the Use of Younger Naval ...

J. L. Robinson - 1882 - 356 pages
...geometrical theorems must be known : (1) The angles at the base of an isosceles triangle are equal. (2) The three angles of a triangle are together equal to two right angles. (3) The angle at the centre of a circle is double the angle at the circumference standing on an equal...

## The Intuitions of the Mind Inductively Investigated

James McCosh - 1882 - 472 pages
...inhabited, even this is not a primary conviction ; we believe it because of secondary testimony. Nay, that the three angles of a triangle are together equal to two right angles, is not a primitive judgment, for it needs other truths coming between to carry our conviction. X But...