| 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... | |
| 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... | |
| 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... | |
| 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,... | |
| 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... | |
| George Park Fisher - Apologetics - 1888 - 166 pages
...never have seen London, but we have not a whit more doubt that London exists than we have that the **sum of the three angles of a triangle is equal to two right** angles. We never saw Napoleon the First, but we are not less certain that Napoleon lived than we are... | |
| George Johnston Allman - Geometry - 1889 - 266 pages
...drawn from the preceding notices. First inference. — Thales must have known the theorem that the **sum of the three angles of a triangle is equal to two right** angles. Pamphila, in (d), refers to the discovery of the property of a circle that all triangles described... | |
| George Irving Hopkins - 1891 - 210 pages
...side of a triangle is less than the sum of the other two, and greater than their difference. 98. The **sum of the three angles of a triangle is equal to two right** angles. Sug. Consult Theorems 58 and 87. 99. If one side of a triangle be extended, the exterior angle... | |
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