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 ## A System of Practical Mathematics: ... With a Plain Account of the Gregorian ...

John Potter - Mathematics - 1753 - 568 pages
...of the Sides is oppofite the given Angle ; but mud be folved by the fecond Rule, Page 224. Now, as the three Angles of every Triangle are equal to two right Angles, or 180°, the Angle at A 36° . 40', being fubtrafted from 180°, leaves 143° . 20', the Sum of the... ## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1762 - 488 pages
...oppofite angles of any quadrilateral figure defcribed in a circle, are together equal to two right T angles. Let ABCD be a quadrilateral figure in the circle ABCD ; any two of its oppofite angles are together equal to two right angles. Join AC, BD ; and becaufe the three angles... ## Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books

Euclid - Geometry - 1765 - 492 pages
...it : I fay, its oppofite angles are equal to two right angles. Join Ac, BD. Then becaufe [by 32. i.] the three angles of every triangle are equal to two right angles, the three angles CAB, ABc, BC A of the triangle ABC will be equal to two right angles. But [by 2I. 3.] the angle c AB... ## A Royal Road to Geometry: Or, an Easy and Familiar Introduction to the ...

Thomas Malton - 1774 - 482 pages
...wanting four ; and by the 2nd, all the external Angles are equal to four Right Angles. Alfo, by the loth, the three Angles of every Triangle are equal to two Right Angles; and all the Angles, about a Point, are equal to four; (2.i.) confequently, fince the three Angles DEF,... ## The Elements of Euclid, Viz: The Errors, by which Theon, Or Others, Have ...

Robert Simson - Trigonometry - 1775 - 534 pages
...PROP. XXII. THEO R. THE oppofite angles of any quadrilateral figure deleribed in a circle, are together equal to two right angles. Let ABCD be a quadrilateral figure in the circle ABCD ; any two of its oppofite angles are together equal to two right angles. Join AC, BD ; and becaufe the three angles... ## The Elements of Euclid,: In which the Propositions are Demonstrated in a New ...

Euclid - Geometry - 1776 - 318 pages
...angles0;, therefore the fix angles ABD, ABC, ACB, v ACD, ADC, ADB, are greater than two right angles: But c the three angles of every triangle are equal to two right angles • therefore the nine angles CBA, BCA, BAC, ACD, CAD, ADC, ADB, ABD, DAB, ate equal to fix right angles... ## The First Six Books: Together with the Eleventh and Twelfth

Euclid - 1781 - 550 pages
...PROP. XXII. THEO R. THE oppofite angles of any quadrilateral figure defcribed in a circle, are together equal to two right angles. Let ABCD be a quadrilateral figure in the circle ABCD ; any two of its oppofite angles are together equal to two right angles. Join AC, BD ; and becaufe the three angles... ## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1781 - 534 pages
...XXTI. THEO R- . THE oppofite angles of any quadrilateral figure deferibed in a circle, are together equal to two right angles. Let ABCD be a quadrilateral figure in the circle ABCD i arry two of its oppofite angle* are together equal to two right angles. Join AC, BD ; and becaufe... ## The Elements of Euclid: With Dissertations Intended to Assist and Encourage ...

Euclid, James Williamson - Euclid's Elements - 1781 - 324 pages
...oppofite angles of it are equal to two right angles. Let AC, BD be joined. And becaufe (by 32. i.) the three angles of every triangle are equal to two right angles; CAB, ABC, BCA the three angles of the triangle ABC are equal to two right angles : but CAB is equal... 