After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles... Introduction and books 1,2 - Page 218by Euclid, Sir Thomas Little Heath, Johan Ludvig Heiberg - 1908Full view - About this book
| Shanti Narayan - Functions - 2007 - 312 pages
...false. Consider, for example, the following statements, some of which are true and some false : (/) The **sum of the three angles of a triangle is equal to two right** angles. (/'/') Every rectangle is a triangle, (ш) The sum of an opposite pair of angles of a cyclic... | |
| Lisa M. Dolling, Arthur F. Gianelli, Glenn N. Statile - Science - 2003 - 716 pages
...geometrical figures have different properties on the different surfaces. On the sheet of paper the **sum of the three angles of a triangle is equal to two right** angles, on the egg, or the sphere, it is larger, on the saddle it is smaller. On the flat paper —... | |
| Euclid - Geometry - 1926
...respectively, the sum of the angles of the whole triangle is (zR - o) + (zR - ft ) - zR = iR - (a + 0). III. **If the sum of the three angles of a triangle is equal to two right** angles, the same is true of all triangles obtained by subdividing it by straight lines drawn from a... | |
| Edmund Whittaker - Science - 1949 - 212 pages
...could be replaced by the assertion that 'it is possible to divide space into equal cubes', or that 'the **sum of the three angles of a triangle is equal to two right** angles', or that 'a triangle exists similar to a given triangle but of arbitrary size '. Any one of... | |
| Schools - 1896
...GEOMETRY.— i. What is Geometry? When are angles supplementary? When complementary? 2. Prove that the **sum of the three angles of a triangle is equal to two right** angles. 3. A straight line can not insersect the circumference of a circle in more than two places.... | |
| James Hopwood Jeans (Sir.) - 1947 - 364 pages
...the angle in a semicircle is less obvious. It is easy to prove it deductively if it is known that the **sum of the three angles of a triangle is equal to two right** angles, but otherwise not. And Thales is hardly likely to have known this; he did not think of an angle... | |
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