 | Bowdoin College - Science - 1870 - 428 pages
...those so easy to gather every day, would be to deny a truth which in its way is as plainly shown as that the sum of the three angles of a triangle is equal to two right angles. If now it is announced to us that for the production of another kind of dropsy there is needed... | |
 | Trinity College (Hartford, Conn.) - 1870 - 1008 pages
...side of a triangle is less than the sum and greater than the difference of the other two sides. 2. The sum of the three angles of a triangle is equal to two right angles. 3. The diagonals of a parallelogram bisect each other. 4. An inscribed angle is measured by... | |
 | Henry Barnard - Education - 1872 - 984 pages
...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... | |
 | Henry Barnard - Education - 1872 - 988 pages
...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... | |
 | New York Board of Education, New York (N.Y.). Board of Education - History - 1873 - 166 pages
...idea of 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... | |
 | Education - 1874 - 508 pages
...derived such 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 - Teaching - 1875 - 294 pages
...idea of 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 - Geometry - 1876 - 384 pages
...therefore 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... | |
 | Humanities - 1877 - 626 pages
...Thales can be 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 - Geometry - 1877 - 416 pages
...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... | |
| |
After remarking that the mathematician positively knows that the sum of the three angles of a triangle is equal to two right angles... 
