 THEOREM. If a straight line, falling on two other straight lines, make the alternate angles equal to each other ; these two straight lines shall be parallel.  A History of Mathematics - Page 292by Florian Cajori - 1893 - 422 pagesFull view - About this book
 | John Playfair - Mathematics - 1806 - 320 pages
...angle EDF. Therefore, if two triangles, &c. QED PROP. XXVII. THEOR. IF a straight line falling upon two other straight lines make the alternate angles equal to one another, these two straight lines are parallel. Let the straight line EF, which falls upon the two straight... | |
 | Euclid - Geometry - 1810 - 554 pages
...Therefore, if' . two triangles, &«. QED Book l. PROP. XXVII. THEOR. IF a straight line falling upon two other straight lines make the alternate angles equal to one another, these two straight lines shall be parallel. Let the straight line EF, which fells upon the two straight... | |
 | Robert Simson - Trigonometry - 1827 - 546 pages
...angle EDF. Therefore, if two triangles, &c. QED PROP. XXVII. THEOR. If a straight line falling upon two other straight, lines make the alternate angles equal to one another^ these two straight lines shall be parallel. Let the straight line EF, which falls upon the two straight... | |
 | Euclides - Geometry - 1841 - 378 pages
...angle EDF. Therefore, if two triangles, &c. QED PROP. XXVII. THEOR. If a straight line, falling upon two other straight lines, make the alternate angles equal to one another, these two straight lines shall be parallel. Let the straight line EF, which falls upon the two straight... | |
 | Education - 1844 - 688 pages
...two angles of a triangle are together less than two right angles. 4. If a straight line falling upon two other straight lines make the alternate angles equal to one another, these two straight lines shall be parallel. 5. The opposite sides and angles of parallelograms are... | |
 | Euclides - 1845 - 546 pages
...third angle BAC to the third angle EDF. Wherefore if two triangles, &c. QED PROPOSITION XXVII. THEOREM. If a straight line, falling on two other straight lines, make the alternate angles equal to each other ; these two straight lines shall be parallel. Let the straight line EF, which falls upon... | |
 | Euclides - 1848 - 52 pages
...angle of the one to the third angle of the other. PROP. XXVII. THEOREM. If a straight line falling upon two other straight lines make the alternate angles equal to one another ; these two straight lines shall be parallel. PROP. XXVIII. THEOREM. If a straight line falling upon... | |
 | 1867 - 336 pages
...which are opposite to the less of the two sides. Are such triangles necessarily equal? SSOTION III. 1. If a straight line, falling on two other straight...lines, make the alternate angles equal to one another; these two straight lines slmll be parallel. Two triangles ABC, DEF are equal iu every respect, AB=DE,... | |
 | Euclides - 1853 - 146 pages
...angle EDF. Therefore if two triangles, &c. QED PROP. XXVII. THEOREM. If a straight line, falling upon two other straight lines, make the alternate angles equal to one another, these two straight lines shall be parallel. Let the straight line EF, which falls upon the two straight... | |
 | Euclides - 1855 - 270 pages
...line which shall make equal angles with two straight lines given in position. PROP. XXVII. THEOREM. If a straight line falling on two other straight lines, make the alternate angles equal to each other ; these two straight lines are parallel. Let the straight line EF, which falls upon the... | |
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