 | Euclid, John Casey - Euclid's Elements - 1885 - 340 pages
...B. LEGENDRE'S AND HAMILTON'S PROOFS or EUCLID, i. xxxn. The discovery of the Proposition that "the sum of the three angles of a triangle is equal to two right angles ' ' is attributed to Pythagoras. Until modern times no proof of it, independent of the theory... | |
 | Euclides - 1885 - 340 pages
...two angles ABC, CDA equal to the sum of the three angles ACD, DAC, CDA of the triangle ACD ; but the sum of the three angles of a triangle is equal to two right angles [I. xxxn.]. Therefore the sum of ABC, CDA is two right angles. Or thus : Let O be the centre... | |
 | Antonio Rosmini-Serbati - 1885 - 668 pages
...mathematical affirmations — for example, "The consequence is contained in the principle," or " The sum of the three angles of a triangle is equal to two right angles " — then the copulative is signifies only ideal being. If the affirmation descends to the... | |
 | Charles Davies - Geometry - 1886 - 352 pages
...equal to the third angle of the triangle. For, the sum of the three angles of a triangle is equal 10 two right angles (Bk. I. Th. xvii) ; and the sum of...CEH are equal to two of the angles, the angle HEF w1ll be equal to the remaining angle of the triangle PROBLEM XI. Three sides of a triangle being given,... | |
 | Education - 1888 - 634 pages
...etc., €tc., and that we shall one day die. On this hypothesis all general knowledge, such as " the sum of the three angles of a triangle is equal to two right angles," is impossible, for this statement transcends the experience of any individual. The second... | |
 | Antonio Rosmini - Psychology - 1886 - 660 pages
...mathematical affirmations — for example, "The consequence is contained in the principle," or " The sura of the three angles of a triangle is equal to two right angles " — then the copulative is signifies only ideal being. If the affirmation descends to the... | |
 | Joseph Baldwin - Educational psychology - 1887 - 332 pages
...Mental Phenomena. — I perceive the beautiful lily, I remember the cheering song. I discern that the sum of the three angles of a triangle is equal to two right angles. I grieve over the loved and lost. I determine to study psychology. I perceive myself remembering,... | |
 | Gabriel Compayré - Education - 1887 - 516 pages
...mentioned above ; but it should be recollected that no "System of mere measurements can ever prove that the sum of the three angles of a triangle is equal to two right angles. (P.) 421. ARE THERE OBJECT-LESSONS IN ARITHMETIC AND GEOMETRY ? — We do not think that there... | |
 | Education - 1887 - 720 pages
...What is an isoscles triangle '( an equilateral triangle ; a scalene triangle f 22-24 Prove that the sum of the three angles of a triangle is equal to two right angles. 26-27. Name three ways in which triangles may be proved equal. 28-30. Prove that in a triangle... | |
 | George Albert Wentworth - Geometry - 1888 - 264 pages
...third side, and their difference is less than the third side. PROPOSITION XXIII. THEOREM. -/ 138. The sum of the three angles of a triangle is equal to two right angles. A Let ABC be a triangle. To prove Z B + Z BCA + ZA = 2 rt. A. Proof. Suppose CE drawn II to... | |
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After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles... 
