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
| Wilbur Fisk Nichols - 1910
...a triangle. With your protractor measure each angle. Add the sum. What is the result? 8. Learn: The **sum of the three angles of a triangle is equal .to two right** angles, or 180°. 9. Can you draw a triangle that shall contain an acute, an obtuse, and a right angle?... | |
| David Eugene Smith - Geometry - 1911 - 339 pages
...with these corollaries, they are helpful for definite reference in later propositions. THEOREM. The **sum of the three angles of a triangle is equal to two right** angles. Euclid stated this as follows : " In any triangle, if one of the sides be produced, the exterior... | |
| Hans Gross - Crime and criminals - 1911 - 514 pages
...they are supposed to be, even when mathematically conceived. The empirical law is established that the **sum of the three angles of a triangle is equal to two right** angles. And yet nobody, ever since the science of surveying has been invented, has succeeded in discovering... | |
| Geometry, Plane - 1911 - 178 pages
...arcs, supplementary angles, incommensurable magnitudes, similarly divided lines. 2. Prove that the **sum of the three angles of a triangle is equal to two right** angles. 3. Complete and prove the following statement: The sum of the squares on two sides of a triangle... | |
| Hans Gross - Crime - 1911 - 514 pages
...they are supposed to be, even when mathematically conceived. The empirical law is established that the **sum of the three angles of a triangle is equal to two right** angles. And yet nobody, ever since the science of surveying has been invented, has succeeded in discovering... | |
| Charles Albert Dubray - Philosophy - 1912 - 624 pages
...be known by experience before their truth is accepted. Thus, after demonstration, the theorem "The **sum of the three angles of a triangle is equal to two right** angles," is seen to express an essential property of all kinds of triangles, true of all triangles... | |
| George Wentworth, George Albert Wentworth, David Eugene Smith - Geometry - 1913 - 470 pages
...side of the transversal are supplementary, the lines are parallel. PROPOSITION XIX. THEOREM 107. The **sum of the three angles of a triangle is equal to two right** angles. c 7 A Given the triangle ABC. To prove that ZA + Z JB+ZC = 2 rt. A. Proof. Suppose BY drawn... | |
| Boris Sidis - Psychology - 1914 - 406 pages
...uniformity. Under similar conditions like results follow. Suppose a geometrician should prove to you that the **sum of the three angles of a triangle is equal to two right** angles, suppose that some sceptic should come in and say, "Yes, that is all right in relation to the... | |
| Charles Ernest Chadsey, James Hamblin Smith - Arithmetic - 1917 - 314 pages
...parts so that you can arrange the angles about a point on one side of a straight line. Show that the **sum of the three angles of a triangle is equal to two right** angles (or 180°). Draw other shaped triangles to show that this principle holds true for any shaped... | |
| Michael Joseph Mahony - Logic - 1918 - 95 pages
...JUDGMENTS are arrived at by the process of deductive reasoning, as when it is demonstrated that "The **sum of the three angles of a triangle is equal to two right** angles". Pure mathematical conclusions are the outcome of mediate analytical judgments. IMMEDIATE SYNTHETIC... | |
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