 | Thomas Stantial - Examinations - 1859 - 352 pages
...and all the angles made by any number of lines meeting in a point are equal to four right angles. B. The three angles of every triangle are equal to two right angles. C. The angles at the base of an isosceles triangle are equal to one another. D. Construct a parallelogram... | |
 | Frederick Augustus Griffiths - Artillery - 1859 - 426 pages
...radii, its sides become the sines of the opposite angles, or the cosines of the adjacent augles. 5. The three angles of every triangle are equal to two right angles ; hence the obilque angles of a right-angled triangle are each other's complements. 6. The sum of the... | |
 | John Fry Heather - Angles (Geometry) - 1859 - 198 pages
...the two angles HI A and '•A HAI; 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 HAI, and therefore... | |
 | Robert Potts - Geometry, Plane - 1860 - 380 pages
...CD. Then any two of its opposite angles shall together be equal to two right angles. 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 - 1862 - 172 pages
...snall be together equal to two right angles. CONSTRUCTION Draw the diagonals AC and DB. 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... | |
 | 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
...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 - 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... | |
 | Robert Potts - 1865 - 528 pages
...Then any two of its opposite angles shall together bfe equal to two right angles. 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... | |
 | 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... | |
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When you have proved that the three angles of every triangle are equal to two right angles... 
