 | John Playfair - 1837 - 332 sider
...triangles, the four oblique angles of which are equal to the three angles of the triangle, therefore the three angles of every triangle are equal to two right angles. ing the Elements. It proceeds, like that of the French Geometer, by demonstrating, in the first place,... | |
 | English monthly tract society - 1838 - 640 sider
...certainty. In mathematical reasoning our knowledge is greater than our ignorance. When you have proved that the three angles of every triangle are equal to two right angles, there is an end of doubt ; because there are no materials for ignorance to work up into phantoms ;... | |
 | Euclides - 1841 - 378 sider
...any two of its opposite angles shall together be equal to two right angles. Join AC, BD; and because the three angles of every triangle are equal* to two right angles, the three * 32. 1. angles of the triangle CAB, viz. the angles CAB, ABC, BCA are equal to two right angles: but... | |
 | John Playfair - 1842 - 332 sider
...triangles, the four oblique angles of which are equal to the three angles of the triangle, therefore the three angles of every triangle are equal to two right angles. Though this method of treating the subject is strictly demonstrative, yet, as the reasoning in the... | |
 | 1844 - 484 sider
...prospect, before a dark cave, or a dreadful precipice. It is not more evident to the mathematician, that the three angles of every triangle are equal to two right angles, than it is to all mankind, that justice and mercy excel tyranny and oppression. 6. Another desolating... | |
 | Robert Halley - 1844 - 646 sider
...weak. He avows in his severest passages that he has as little angry feeling, as when he says, that " the three angles of every triangle are equal to two right angles ;" but how much more Christian-like may be this cool, apathetic mode of vituperation, the sardonic... | |
 | 1844 - 434 sider
...proposition, too, would follow the converse of the first one, if ever the sum differed from 180". PROP. III. The three angles of every triangle are equal to' two right angles. B ' Let ABC be any equilateral trlanglfe ; ./\ / \ bisect its angles, which obviously will {[ •£... | |
 | Euclid - 1845 - 218 sider
...: any two of its opposite angles are together equal to two right angles. Join AC, BD : And because the three angles of every triangle are equal* to two right angles, the three angles of the triangle CAB, viz. the angles CAB, ABC, BCA are equal to two right angles : But the angle CAB... | |
 | Euclides - 1845 - 546 sider
...any two of its opposite angles shall together be equal to two right angles. Join AC, BD. And because the three angles of every triangle are equal to two right angles, (i. 32.) the three angles of the triangle CAB, viz. the angles CAB, ABC, BCA, are equal to two right... | |
 | Plato - 1845 - 460 sider
...say it is compelled to affirm, and does affirm this, with the same confidence as the proposition that the three angles of every triangle are equal to two right angles, or that two bodies cannot occupy the same space. Even this, notwithstanding it lies at the foundation... | |
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When you have proved that the three angles of every triangle are equal to two right angles... 
