 | Thomas Hill - 1863 - 164 pàgines
...thr gles about the point A, and their sum is plainly two ! angles. 37. The mode of proving that the sum of the three angles of a triangle is equal to two right angles, by cutting a piece of card, is called experimental proof. It is of very little use in mathematics,... | |
 | C. Davies - 1867 - 342 pàgines
...line DEFAt any point, as E, make D•H the angle DE C equal to one of the given angles, and then CEH equal to a second, by Prob- VIII ; then will the angle HEF be equal to the third angle of the triangleFor, the sum of the three angles of a triangle is equal to two right angles (Bk- I- Th- xvii)... | |
 | New York (N.Y.). Board of Education. Superintendent of Schools - 1867 - 132 pàgines
...the necessaries of life, or of filling the pocket, it may be difficult to determine. That the s\im of the three angles of a triangle is equal to two right angles, and that the Greeks drove back the Persian invaders, are facts which per se might appear to... | |
 | James Maurice Wilson - 1868 - 132 pàgines
...it make the angles FGH=A, and HGK=B, then KGE will equal the third angle of the triangle, since the sum of the three angles of a triangle is equal to two right angles. At C and D make angles equal to HGK and KGE, and let their sides meet in O; then OCD is the... | |
 | 1869 - 794 pàgines
...great.y developed. For example, the child can be led to discover, by means of his protractor, that the sum of the three angles of a triangle, is equal to two right-angles, or that the vertical angles formed by the intersection of two lines, are equal. When... | |
 | Trinity College (Hartford, Conn.) - 1870 - 1008 pàgines
...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... | |
 | Bowdoin College - 1870 - 428 pàgines
...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... | |
 | Henry Barnard - 1872 - 988 pàgines
...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 pàgines
...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 pàgines
...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... | |
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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... 
