 | Henry Barnard - 1872 - 988 σελίδες
...catch either into other cogged wheels, or into pinions, or into trundles, Ac. Of the Triangk. — The sum of the three angles of a triangle is equal to two right-angles, Ac. Of similar Triangles. — Two triangles are similar when the angles of one are equal... | |
 | Henry Barnard - 1872 - 984 σελίδες
...catch either into other cogged wheels, or into pinions, or into trundles, Ac. Of the Triangle. — The sum of the three angles of a triangle is equal to two right-angles, Ac. Of eimiiar Triangle*. — Two triangles are similar when the ingles of one ar» equal... | |
 | New York Board of Education, New York (N.Y.). Board of Education - 1873 - 166 σελίδες
...side in -each respectively equal ; (c) when they have three sides in each respectively equal. 6. The sum of the three angles of a triangle is equal to two right angles. I7. The sum of the interior angles of a polygon is equal to twice as many right angles as the... | |
 | 1874 - 520 σελίδες
...heartfelt pleasure and profound satisfaction from the contemplation of that wonderful truth, that the sum of the three angles of a triangle is equal to two right angles. My friend, who sits before me, used to take particular delight in putting this at me, when... | |
 | 1874 - 508 σελίδες
...heartfelt pleasure and profound satisfaction from the contemplation of that wonderful truth, that the sum of the three angles of a triangle is equal to two right angles. My friend, who sits before me, used to take particular delight in putting this at me, when... | |
 | Henry Kiddle, Thomas F. Harrison, Norman Allison Calkins - 1875 - 294 σελίδες
...equality as a definite fact, and inequality indefinitely. Thus, it is required to be proved that the sum of the three angles of a triangle is equal to two right angles ; also, that, of any two sides of a triangle, that which lies opposite to the greater angle... | |
 | Aaron Schuyler - 1876 - 384 σελίδες
...equal. 76. Exercises. 1. Prove by means of the annexed diagram, in which DE is parallel to AC, that the sum of the three angles of a triangle is equal to two right angles. 2. The sum of the three straight lines drawn from any point within a triangle to the vertices... | |
 | George Albert Wentworth - 1877 - 416 σελίδες
...a point to a straight line make equal acute angles with that line. PROPOSITION XXL THEOREM. 98. The sum of the three angles of a triangle is equal to two right angles. BE C Let ABC be a triangle. We are to prove ZB + ZB CA + ZA = two rt. A Draw CE II to AB, and... | |
 | 1877 - 626 σελίδες
...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 [<f], refers to the discovery of the property of a circle that all triangles described... | |
 | George Albert Wentworth - 1877 - 416 σελίδες
...point to a straight line make equal acute angles with that line. PROPOSITION XXI. THEOREM. 98. The sum of the three angles of a triangle is equal to two righd angles. BE C Let ABC be a triangle. We are to prove Z. B + Z. BCA + Z. A = two rt. A. Draw CE... | |
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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... 
