 | Thomas Kerigan - 1828 - 776 σελίδες
...base C I. The measure of the angle CHI is thus determined. In all quadrilateral or four-sided figures, the sum of the four angles is equal to four right angles, or 360 degrees. Now, in the quadrilateral figure AHIF, since three of the angles are given, the remaining or obtuse... | |
 | John Playfair - 1829 - 210 σελίδες
...therefore A = -J of 2 right angles, or f of one right angle. ED. Cor.. 6. In every quadrilateral figure -R the sum of the four angles is equal to four right angles. For if a line BC be drawn between two opposite angles of any quadrilateral figure ACDB, it will divide... | |
 | Thomas Kerigan - 1838 - 804 σελίδες
...base C I. The measure of the angle CHI is thus determined. In all quadrilateral or four-sided figures, the sum of the four angles is equal to four right angles, or 360 degrees. Now, in the quadrilateral figure A II IF, since three of the angles are given, the remaining or obtuse... | |
 | William Chauvenet - 1871 - 380 σελίδες
...therefore, each of the sums A -f- B and C + D is equal to one-half the sum of the four angles. But the sum of the four angles is equal to four right angles (100) ; therefore, A -f- B is equal to two right angles, and the lines AD and BC&re parallel (56).... | |
 | William Chauvenet - 1872 - 382 σελίδες
...therefore, each of the sums A + jB and C -)- D is equal to one-half the sum of the four angles. But the sum of the four angles is equal to four right angles (100) ; therefore, A -f- B is equal to two right angles, and the lines AD and BC are parallel (56).... | |
 | Aaron Schuyler - 1876 - 384 σελίδες
...be two consecutive angles, for example, A and E, whose sum does not exceed two right angles, since the sum of the four angles is equal to four right angles. Let AC and EC be the bisectors of the angles A and E. The sum of the angles, CAE, CEA, is less than... | |
 | Adrien Marie Legendre - 1882 - 194 σελίδες
...three sides of the pentagon ; hence the angle BFD is equal to the angle BCD. In the quadrilateral BCDF, the sum of the four angles is equal to four right angles (B. I, P. XXVI, C. 1), and as the opposite angles B and D are equal, and also C and F, the sum of the... | |
 | Thomas Fenwick, Thomas Baker - 1888 - 246 σελίδες
...45.) 11. In any four-sided right-lined figure, called a square parallelogram, rhombus, trape2ium, &c., the sum of the four angles is equal to four right angles, or 360°.- —(Euc. b. 1, p. 32.) 12. The sum of all the angles of any right-lined figure (though it contain never... | |
 | Gardner Chace Anthony - 1894 - 190 σελίδες
...is greater than a right angle. V ' •'*•' When one straight line crosses another straight line, the sum of the four angles is equal to four right angles ; any two adjacent angles are equal to two right angles, and are said to be supplementary to each other.... | |
 | Walter William Rouse Ball - 1901 - 580 σελίδες
...whatever be the sum of the angles AFG and FGC such also must be the sum of the angles FGD and BFG. But the sum of the four angles is equal to four right angles, and therefore the sum of the angles BFG and FGD must be equal to two right angles. Ptolemy wrote another... | |
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But the sum of the four angles is equal to four right angles (100) ; therefore, A -f- B is equal to two right angles, and the lines AD and BC&re parallel (56). 