 | Sir Norman Lockyer - Electronic journals - 1902 - 1074 pages
...the plane than Prop. xx. in § 449, viz., " The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane." It is advantageous to know, not only the least and the greatest angles between a fixed... | |
 | Sir Norman Lockyer - Electronic journals - 1902 - 688 pages
...the plane than Prop. xx. in § 449, viz., " The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line ofthat plane." It is advantageous to know, not only the least and the greatest angles between a fixed... | |
 | Education - 1902 - 730 pages
...one, common perpendicular. 2. Prove: The acute angle that a straight makes with its own projection on a plane is the least angle it makes with any line in that plane. 3. (a) Prove: The sum of the face angles of any convex polyhedral angle is less than a... | |
 | Evan Wilhelm Evans - Geometry - 1884 - 170 pages
...3). THEOREM IV. When an oblique line meets a plane, the angle which it makes with its own projection is the least angle it makes with any line in the plane. Let DC be the projection of AD upon the plane MS, and DB be any other line in the plane drawn from... | |
 | William Chauvenet, William Elwood Byerly - Geometry - 1887 - 331 pages
...plane is a straight line. PROPOSITION XIX. The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane. PROPOSITION XX. The sum of any two face angles of a triedral angle is greater than the... | |
 | William Chauvenet, William Elwood Byerly - Geometry - 1887 - 336 pages
...plane is a straight line. PROPOSITION XIX. The acute angle which a straight line makes with ite own projection upon a plane is the least angle it makes with any line of that plane. PROPOSITION XX. The sum of any two face angles of a triedral angle is greater than the... | |
 | William Chauvenet - 1893 - 340 pages
...plane is a straight line. PROPOSITION XIX. The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane. PROPOSITION XX. The sum of any two face angles of a triedral angle is greater than the... | |
 | John Macnie - Geometry - 1895 - 386 pages
...PROPOSITION XXIII. THEOREM. 482. The acute angle formed by a straight line with its own projection on a plane, is the least angle it makes with any line in that plane. Given: Angle ABC, formed by AB with its projection BC on plane MN ; To Prove: Angle ABC... | |
 | Harvard University - Geometry - 1899 - 39 pages
...upon a plane is a straight line. THEOREM XX. The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane. THEOREM XXI. The sum of any two face angles of a triedral angle is greater than the... | |
 | Thomas Franklin Holgate - Geometry - 1901 - 462 pages
...LINES AND PLANES IN SPACE PROPOSITION XX 449. The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane. Let AB be any straight line oblique to the plane L, and let BC be its projection upon... | |
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The acute angle which a straight line makes with its own projection upon a plane is the least angle it makes with any line of that plane. 
