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 ## Hermathena, Volume 5

Humanities - 1885 - 480 pages
...isosceles, and lastly in the scalene; those that came after them proved the general theorem as follows: — "The three angles of every triangle are equal to two right angles." So also in the sections of a cone ; for they viewed the so-called " section of the rightangled cone... ## Practical Surveying: A Text-book for Students Preparing for Examinations Or ...

George William Usill - Surveying - 1889 - 306 pages
...the two interior angles H i A and HA i ; and because the angles A v H 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 s EH are together equal to the two angles AH v and HA i, and therefore... ## Greek Geometry from Thales to Euclid

George Johnston Allman - Geometry - 1889 - 266 pages
...and lastly in the scalene ; those that came after them proved the general theorem as follows : — " The three angles of every triangle are equal to two right angles." So also in the sections of a cone ; for they viewed the so called " section of the rightangled cone... ## The Elements of Plane and Solid Geometry: With Numerous Exercises

Edward Albert Bowser - Geometry - 1890 - 420 pages
...a quadrilateral have two of its opposite sides parallel, and the other two equal but not parallel, any two of its opposite angles are together equal to two right angles. 24. On the sides AB, BC, and CD of a parallelogram. ABCD three equilateral triangles are described,... ## Rider Papers on Euclid: Books i and Ii, Graduated and Arranged in Order of ...

Rupert Deakin - Euclid's Elements - 1891 - 102 pages
...quadrilateral figure has two of its opposite sides parallel, and the other two sides equal but not parallel, any two of its opposite angles are together equal to two right angles. 6. The parts of all perpendiculars to two parallel lines intercepted between them are equal. PART V.... ## Euclid's Elements of Geometry, Books 1-6

Henry Martyn Taylor - 1893 - 486 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. 3. If a straight line which joins the extremities of two equal straight lines, not parallel, make the... ## Euclid's Elements of Geometry, Books 1-6; Book 11

Henry Martyn Taylor - Euclid's Elements - 1895 - 708 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. 3. If a straight line which joins the extremities of two equal straight lines, not parallel, make the... ## The Essentials of Logic, Being Ten Lectures on Judgment and Inference

Bernard Bosanquet - Logic - 1895 - 188 pages
...Predicate. " William Pitt was a great statesman "=" There ' was a great statesman named William Pitt " ; " The three angles of every triangle are equal to two right angles " = " There are figures known as triangles with their three angles equal to two right angles " ; "... ## The Essentials of Logic: Being Ten Lectures on Judgment and Inference

Bernard Bosanquet - Logic - 1897 - 188 pages
...Predicate. " William Pitt was a great statesman " = " There was a great statesman named William Pitt" ; " The three angles of every triangle are equal to two right angles " = " There are figures known as triangles with their three angles equal to two right angles"; "All... 