| Industrial arts - 1831 - 532 pages
...has been before proved that the angle ADe is an acute angle of 90 degrees, whence it follows that as the three angles of a triangle are together equal to two right angles, the remaining angle fh D must likewise be an acute angle of 90 degrees, and, as before, since the two... | |
| Francis Lieber, Edward Wigglesworth - Encyclopedias and dictionaries - 1832 - 656 pages
...numbers. Of tho geometrical theorems which are ascribed to him, the following are the most important : The three angles of a triangle are together equal to two right angles ; and in aright-angled triangle, the square of the hypothenuse is equal to the sum of the squares of the... | |
| Leonhard Euler, Sir David Brewster - Astronomy - 1833 - 442 pages
...impossible to draw any conclusion with respect to real objects ; thus, when I have demonstrated that the three angles of a triangle are together equal to two right angles, this is a property belonging only to an abstract triangle, and not at all to one really existing. 32... | |
| Leonhard Euler, Sir David Brewster - Astronomy - 1833 - 446 pages
...impossible to draw any conclusion with respect to real objects; thus, when I have demonstrated that the three angles of a triangle are together equal to two right angles, this is a property belonging only to an abstract triangle, and not at all to one really existing. You... | |
| Biography - 1833 - 504 pages
...advanced as far as the thirty-second proposition of the first book of Euclid. He had perceived that the three angles of a triangle are together equal to two right ones, and was searching for a satisfactory proof, when his father surprised him in his forbidden speculations.... | |
| Mathematics - 1835 - 684 pages
...notwithstanding, of opinion, that the grand truth with which it is so intimately connected, viz., that " the three angles of a triangle are together equal to two right angles," may be referred to the general principle of Homogeneity. Of this it is unnecessary to say more in this... | |
| American Institute of Instruction - 1836 - 332 pages
...for a thousand years, furnishes no absolute assurance that it will rise tomorrow. But the troth that the three angles of a triangle are together equal to two right angles, ia made as certain by a single demonstration, as it could be by a thousand. Apply now this illustration... | |
| American Institute of Instruction - Education - 1836 - 328 pages
...for a thousand years, furnishes no absolute assurance that it will rise tomorrow. But the truth that the three angles of a triangle are together equal to two right angles, is made as certain by a single demonstration, as it could be by a thousand. Apply now this illustration... | |
| Euclid, James Thomson - Geometry - 1837 - 410 pages
...the angles at its base BD double of the third angle A : which was to be done. Cor. Since i; I. 32.) the three angles of a triangle are together equal to two right angles, it is plain, that the angle A is one-fifth, and each of the* angles at the base BD, two-fifths of two... | |
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