6.R.2. A RIGHT ANGLE IS OBTUSE
Ball. MRE, 1st ed., 1892, pp. 32 33. See 6.R.1. In the 3rd ed., 1896, pp. 40-41, he adds the heading: To prove that a right angle is equal to an angle which is greater than a right angle.
Mittenzwey. 1895?. Prob. 331, pp. 58 & 106; 1917: 331, pp. 53 & 101.
Carroll-Collingwood. 1899. Pp. 266 267 (Collins 191-192). An obtuse angle is sometimes equal to a right angle. Carroll-Gardner, p. 65, mentions this and says it was not original with Carroll.
H. E. Licks. 1917. Op. cit. in 5.A. Art. 82, p. 56.
W. A. Bagley. Puzzle Pie. Op. cit. in 5.D.5. 1944. Call Mr. Euclid -- No. 16: To prove one right angle greater than another right angle, pp. 18-19. "Here again, if you take the trouble to draw an accurate diagram, you will find that the "construction" used for the alleged proof is impossible."
E. A. Maxwell. Note 2121: That every angle is a right angle. MG 34 (No. 307) (Feb 1950) 56 57. Detailed demonstration of the error.
Dostları ilə paylaş: |
