 | Horace Wilmer Marsh, Annie Griswold Fordyce Marsh - Mathematics - 1914 - 270 pages
...angle. Finish the demonstration. VIII THEOREM 32 The angle which a line makes with its projection on a plane is the least angle which it makes with any line in the plane. Represent by a construction lina a side of the angle which the line makes with any other... | |
 | Webster Wells, Walter Wilson Hart - Geometry - 1916 - 504 pages
...1 MN. PROPOSITION XXI. THEOREM 505. Tlie acute angle between a straight line and its projection on a plane is the least angle which it makes with any line drawn in the plane through its foot. Hypothesis. BC is the projection of AB on plane MN. BD is any... | |
 | John H. Williams, Kenneth P. Williams - Geometry, Solid - 1916 - 184 pages
...angle equal to the given angle? 568. THEOREM. The acute angle which a line makes with its projection on a plane is the least angle which it makes with any line in the plane through its foot. Given line AB, BC its projection on MN, and BD any other line in MN... | |
 | Fletcher Durell, Elmer Ellsworth Arnold - Geometry, Solid - 1917 - 220 pages
...BD. PROPOSITION XXI. THEOREM 2. §§482, 488, 436. 3. Why? 4. Why? 5. § 476. 6. § 123. QE.D. 494. The acute angle which a straight line makes with its own projection upon a plane not perpendicular to the given line, is the least angle it makes with any line of that plane. N Given... | |
 | Claude Irwin Palmer - Geometry, Solid - 1918 - 192 pages
...Proof. Make BD = BC, and draw AC and AD. ThenZABC<^ABD. §259 586. Definition. The acute angle that a straight line makes with its own projection upon a plane is called the inclination of the line to the plane, or the angle that the line makes with the plane. EXERCISES... | |
 | Claude Irwin Palmer, Daniel Pomeroy Taylor - Geometry - 1918 - 460 pages
...Proof. Make BD = BC, and draw AC and AD. Then ZABC < ZABD. § 259 586. Definition. The acute angle that a straight line makes with its own projection upon a plane is called the inclination of the line to the plane, or the angle that the line makes with the plane. EXERCISES... | |
 | Charles Austin Hobbs - Geometry, Solid - 1921 - 216 pages
...prove the converse of Prop. 238. Proposition 239 Theorem The acute angle which a line makes with its projection upon a plane is the least angle which it makes with any line in the plane. Hypothesis. AC is the projection of the line AB upon the plane MN, and AD is any other... | |
 | Raleigh Schorling, William David Reeve - Mathematics - 1922 - 460 pages
...angle with its projection upon the plane. 293. Theorem. The acute angle which a line makes with its projection upon a plane is the least angle which it makes with any line of the plane. A FIG. 282 SUGGESTION. Let BC (Fig. 282) be the projection of AB upon the plane TT, and... | |
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The acute angle which a straight line makes with its own projection upon a plane is the least angle which it makes with any line of that plane. 
