 | abbé Rossignol (Jean-Joseph) - Geometry - 1787 - 190 pages
...confequently, the angles ACD, FCB, which are meafured by thefe two arcs, are alfo equal. PROP. XIII. i If a line is perpendicular to one of two parallel lines, it is alfo perpendicular to the other. N G Let AB, CD be two parallel lines : if the line FO makes right... | |
 | Benjamin Greenleaf - Geometry - 1862 - 518 pages
...equal to 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 - 1861 - 638 pages
...equal to 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 C D. PBOPOSITION XX11I. — THEOREM.... | |
 | Benjamin Greenleaf - Geometry - 1863 - 504 pages
...equal to 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
...are equal to 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
...equal to 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
...equal to 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
...parallel. 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±... | |
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If a line is perpendicular to one of two parallel lines, it is perpendicular to the other also. 
