| William Thomas READ - 1862 - 144 pages
...proved may be obtained, which shows them to be true for any triangle. • We know (by Eu. 1, 32), that **the three angles of every triangle are equal to two right angles** ; therefore those of ABC are equal to two right angles ; and since B = 90°, therefore A + C = 90°,... | |
| Euclides - 1864 - 448 pages
...the circle ABCD. Then any two of its opposite angles shall together be equal to two right angles. c **Join AC, BD. And because the three angles of every triangle are equal to two right angles,** (I. 32.) the three angles of the triangle CAB, viz. the angles CAB, ABC, BCA, are equal to two right... | |
| Euclides - 1864 - 262 pages
...XXII. THEOREM. The opposite angles of any quadrilateral figure inscribed in a circle, are together **equal to two right angles, Let ABCD be a quadrilateral figure in the circle ABCD.** Then any two of its opposite angles shall together be equal to two right angles. .0 Join AC, BD. And... | |
| Robert Potts - 1865 - 528 pages
...PROPOSITION XXn. THEOREM. The opposite angles of any quadrilateral figure inscribed in a circle, are together **equal to two right angles. Let ABCD be a quadrilateral figure in the circle** AB CD. Then any two of its opposite angles shall together bfe equal to two right angles. Join AC, BD.... | |
| Euclides - 1865 - 402 pages
...snall be together equal to two right angles. CONSTRUCTION Draw the diagonals AC and I)B. DEMONSTRATION **Because the three angles of every triangle are equal to two right angles,** (I. 32) the three angles of the triangle CAB, viz. the angles CAB, ABC, BCA, are equal to two right... | |
| John Fry Heather - Mathematical instruments - 1866 - 228 pages
...the two angles HI A and '•* HA i ; and because the vertical angles AVH and IVE are equal, and that **the three angles of every triangle are equal to two right angles,** therefore the two angles VIE and s EH are, together, equal to the two angles AH v and HA i, and therefore... | |
| Isaac Todhunter - Euclid's Elements - 1867 - 426 pages
...than a semicircle, is less than a right angle. And because ABCD is a quadrilateral figure in a circle, **any two of its opposite angles are together equal to two right angles** ; [III. 22. therefore the angles ABC, ADC are together equal to two right angles. But the angle ABC... | |
| Euclid, Isaac Todhunter - Euclid's Elements - 1867 - 424 pages
...a quadrilateral have two of its opposite sides parallel, and the two others equal but not parallel, **any two of its opposite angles are together equal to two right** 74. If a straight lino which joins the extremities of two equal straight lines, not parallel, make... | |
| Robert Potts - 1868 - 434 pages
...circle A BCD. Then any two of its opposite angles shall together be equal to two right anglss. .0 Jam **AC, BD. And because the three angles of every triangle are equal to two right angles,** (I. 32.) the three angles of the triangle CAB, viz. the angles CAB, ABC, BCA, are equal to two right... | |
| John Fry Heather - Drawing instruments - 1871 - 224 pages
...two interior angles H i A and HA i ; and because the vertical angles AVH and iv E are equal, and that **the three angles of every triangle are equal to two right angles,** therefore the two angles VIE and SEE are, together, equal to the two angles AH v and HA i, and therefore... | |
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