 | 1898 - 228 sider
...circular sheet of tin 16 inches in diameter and weighing 8.2 ounces per square foot. JUNE 1896. (a) 1. The sum of the three angles of a triangle is equal to two right angles. 2. Construct a circle having its center in a given line and passing through two given points.... | |
 | William James Milne - 1899 - 326 sider
.... : the required ¿. = 180° - 76° = 104°. Ex. 59. Show by each of the following figures that the sum of the three angles of a triangle is equal to two right angles, assuming that the construction lines чrе drawn as they appear to be drawn. Proof. (1) §... | |
 | William James Milne - 1899 - 398 sider
...49°, and 74° ? PLANE GEOMETRY.— BOOK I. Ex. 59. Show by each of the following figures that the sum of the three angles of a triangle is equal to two right angles, assuming that the construction lines are drawn as they appear to be drawn. Proposition XXIII... | |
 | Charles Austin Hobbs - 1899 - 266 sider
...angles of an inscribed quadrilateral are supplementary. Ex. 283. Prove by the use of Prop. 124 that the sum of the three angles of a triangle is equal to two right angles. Proposition 125. Problem. 158. At a given point in a given straight line, to erect a perpendicular... | |
 | George Albert Wentworth - 1899 - 496 sider
...sides opposite the equal angles are called homologous sides. PROPOSITION XVIII. THEOREM. 129. Tlie sum of the three angles of a triangle is equal to two right angles. BE A c ~F Let A, B, and BCA be the angles of the triangle ABC. To prove that ZA + ZB + Z BCA... | |
 | George Albert Wentworth - 1899 - 278 sider
...sides opposite the equal angles are called homologous sides. PROPOSITION XVIII. THEOREM. 129. Tfie sum of the three angles of a triangle is equal to two right angles. Let A, B, and BCA be the angles of the triangle ABC. To prove that ZA + ZB + Z BCA = 2 rt.... | |
 | Thomas Franklin Holgate - 1901 - 462 sider
...equals the sum of Zs CAB and CBA That is, Z.ACD equals the sum of Zs CAB and CBA. 101. COROLLARY I. The sum of the three angles of a triangle is equal to two right angles. 102. COROLLARY II. The two acute angles of any right triangle are complementary ; ie their... | |
 | 1901 - 548 sider
...pentagon are 40.5, 30.6'>, 51.25, 32.75, and 36.85; find the perimeter. Ans. 192 ft. TRIANGLES. 47. The sum of the three angles of a triangle is equal to two right angles, <>r 180°. Thus, the sum of the three angles A, B, and C, Fig. 31, is 59° + 73° + 48° =... | |
 | William T. Harris, A. M., LL. D. - 1902 - 420 sider
...of mathematical demonstration. No experimental process can ever establish the general truth that the sum of the three angles of a triangle is equal to two right angles. We should not confound " geometrical recreations'" with geometrical science.—(P.) t Isoperimetric... | |
 | 1903 - 692 sider
...uniformly. Casey (El. of Euclid, 8th ed., p. 299) says : " 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... | |
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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... 
