Books Books The opposite angles of any quadrilateral figure described in a circle, are toe/ether equal to two right angles. Let ABCD be a quadrilateral figure in the circle ABCD : any two of its opposite angles are together equal to two right angles. Euclid in Paragraphs: The Elements of Euclid: Containing the First Six Books ... - Page 71
by Euclid - 1845 - 199 pages ## The Elements of Plane and Solid Geometry: With Chapters on Mensuration and ...

Isaac Sharpless - Geometry - 1879 - 282 pages
...circle are together equal to two right angles. Let AB CD be a quadrilateral figure in the circle AB CD; any two of its opposite angles are together equal to two right angles. Join AC, BD. The angle CAB is equal (III. 17) to the angle CDB, because they are in the same segment BADC, and the... ## Proceedings of the Royal Philosophical Society of Glasgow, Volume 11

Royal Philosophical Society of Glasgow - Science - 1879 - 636 pages
...of acting independently of each other, and in co-operation with each other. When I demonstrate that the three angles of every triangle are equal to two right angles, or that in a righi^angled triangle the square upon the side subtending the right angle is equal to... ## The Elements of Euclid for the Use of Schools and Colleges: With Notes, an ...

Isaac Todhunter - Euclid's Elements - 1880 - 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... ## The Elements of geometry; or, The first six books, with the eleventh and ...

Euclides - Euclid's Elements - 1881 - 236 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...angles are together equal to two right angles. Join AC and B D. The angle CAB is equal to the angle CDB (III. 21), because they are in the same segment CDAB.... ## The Cambridge Examiner, Volume 3

Education, Higher - 1883 - 536 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 angles. 15. If a solid angle be contained by three plane angles, any two of them are together greater than... ## Practical geometry for art students

John Carroll (art master.) - Geometry - 1881 - 100 pages
...angle at M. Produce the lines till they meet in O. The angle at O will be equal to the angle at N ; for the three angles of every triangle are equal to two right angles. — Euclid i. 32 cor. Problem 15. — To construct an isosceles triangle, the base FG and the vertical... ## The Diet cure

Thomas Low Nichols - 1881 - 134 pages
...abstinence, which is safe and sure. All this is like saying over and over again, two and two make four : the three angles of every triangle are equal to two right angles : things which are equal to the same thing are equal to each other. A natural diet is always a condition... ## The Elements of Plane and Solid Geometry: With Chapters on Mensuration and ...

Isaac Sharpless - Geometry - 1882 - 292 pages
...18. Theorem. — The opposite angles of any quadrilateral figurt described in a circle are together equal to two right angles. Let ABCD be a quadrilateral...are together equal to two right angles. Join AC, BD. The angle CAB is equal (III. 17) to the angle CDB, because they are in the same segment BADC, and the... ## The Elements of Euclid for the Use of Schools and Colleges: Comprising the ...

Euclid, Isaac Todhunter - Euclid's Elements - 1883 - 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... 