| Benjamin Greenleaf - Geometry - 1862 - 518 pages
...two right angles (Prop. I.) ; hence BGH, GHD are also equal to two right angles. 87. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other ; thus EF (Art. 85), perpendicular to AB, is perpendicular to CD. PROPOSITION XXIII. — THEOREM. 88.... | |
| Benjamin Greenleaf - Geometry - 1862 - 532 pages
...two right angles (Prop. I.) ; hence BGH, GHD are also equal to two right angles. 87. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other ; thus EP (Art. 85), perpendicular to AB, is perpendicular to CD. PROPOSITION XXIII. — THEOREM. 88.... | |
| Benjamin Greenleaf - Geometry - 1863 - 504 pages
...two right angles (Prop. I.) ; hence BGH, GHD are also equal to two right angles. 87. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other; thus EF (Art. 85), perpendicular to AB, is perpendicular to CD. PROPOSITION XXIII. — THEOREM. 88.... | |
| Benjamin Greenleaf - Geometry - 1868 - 340 pages
...two right angles (Prop. I.); hence BGH, GHD are also equal to two right angles. 87. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other ; thus EF (Art. 85), perpendicular to AB, is perpendicular to CD. PROPOSITION XXIII. — THEOREM. "... | |
| Benjamin Greenleaf - Geometry - 1873 - 202 pages
...two right angles (Theo. I.) ; hence BGH, GHD are also equal to two right angles. 65. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other. THEOREM XVIII. 66. If two angles have their sides parallel, each to each, and tying in the same direction,... | |
| Benjamin Greenleaf - Geometry - 1874 - 206 pages
...two right angles (Theo. I.) ; hence BGH, GHD are also equal to two right angles. 65. Cor. If a line is perpendicular to one of two parallel lines, it is perpendicular to the other. THEOREM XVIII. 66. If two angles have their sides parallel, each to each, and lying in the same direction,... | |
| George Albert Wentworth - Geometry - 1877 - 416 pages
...Alternateexterior angles. 2/3 1/4 6/7 5/8 GEOMETRY. — BOOK I. PROPOSITION X. THEOREM. 67. If a straight line be perpendicular to one of two parallel lines, it is perpendicular to the other. II •: С Let AB and EF be two parallel lines, and let HK be perpendicular to A B. We are to prove... | |
| George Albert Wentworth - Geometry, Modern - 1881 - 266 pages
...and 8, 3 and 7 are called Exterior-interior angles. PROPOSITION X. THEOREM. 67. If a straight line be perpendicular to one of two parallel lines, it is perpendicular to the other. H M -._ -—-... С N К Let A В and EF be two parallel lines, and let HK be perpendicular to A B.... | |
| George Albert Wentworth - Geometry - 1888 - 264 pages
...This method of proof is called the indirect method. PROPOSITION VII. THEOREM. 102. If a straight line is perpendicular to one of two parallel lines, it is perpendicular to the other. H: o -It E K Let AB and EF be two parallel lines, and let HK 63 perpendicular to AB. To prove HK±... | |
| Education - 1891 - 214 pages
...because the majortiy use the science. The course of reasoning by which we prove, "If one straight line Is perpendicular to one of two parallel lines, it is perpendicular to the other," is not gone through with to ascertain tbe truth of a statement so evident, but to train the young mind... | |
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