As shown in the chart, we draw a summary of the process of parallel lines using direct feet and triangles: e. E., so that the two lines are known to prove ab/cd2, and the two lines are known to demonstrate that ab/cd2: two lines are cut off by the third line, and that, if there is an internal error, the two lines are known by the movement position behind and behind the triangle, / 1 and 2 are simultaneous and equal, two parallel lines are drawn. 3? Parallel line determination method: three straight lines, if the same angle 4?? 2? Geometric;) ii, parallel line determination method 2: (may be supported by determination method 1) 1 ? As shown in right chart, known/ 1-2/3 attest: ab/cd attests: then the two straight lines simply say: in error angles, 4? (iii) 3 parallel line determination method: two straight lines are confirmed by third straight line, 1) 1 ? ? ?, as in right chart, known/ = 180°, attest: ab//cd method i: attesting with determination method 1; b/ cd method i: attesting with determination method 1; b/ b) 2 parallel line determination method: two straight lines are confirmed by the third straight line, if it is simply stated with the side: with side angles 1 + 4 = 180°; b/ cd method i: using determination method 1 attest? B) 2 cross line: 2 cross line: 2 cross lines: with side, two straight lines; b : two straight lines? B ? B ? B ? B ? B ? 2 cross-c ^.(1) 14 pages of exercise question 1(2) 15 pages of practice question 4 of 5. 2 (3) the following conditions cannot be determined: a/b (d. / 2+/4 = 1801 = / 2; 2/ 3 = 6; a. 1/ 1 = 2 b? / 1 = 2 c? / 1 + / 4 = 180 5. As shown in figure 6, line a, d. / 2 + / 4 = 1801 = / 2; 2/ 3 = 6; 3/ 4 + 7 = 180 ° 4/ 5 ii/ with the conditions for judging a/b as shown in figure 6. 6 (serial numbers only) 6. As in figure, if / 112/2, the following conclusion is correct (a. Ad/bc b. Ab/ cdc. / 3ii/4 d. / aii/ c7? As in figure, / 120/ 2=3, line li, )
