Books Books From this it is manifest, that if one angle of a triangle be equal to the other two, it is a right angle, because the angle adjacent to it is equal to the same two; and when the adjacent angles are equal, they are right angles. A Royal Road to Geometry: Or, an Easy and Familiar Introduction to the ... - Page 178
by Thomas Malton - 1774 - 440 pages ## Euclid's Elements of Geometry: Chiefly from the Text of Dr. Simson, with ...

Robert Potts - Geometry, Plane - 1876 - 446 pages
...a circle the angle in a semicircle is a right angle ; &c. UF.U. COR. From this it is manifest, that if one angle of a triangle be equal to the other two, it is a right angle : because the angle adjacent to it is equal to the same two ; (I. 32.) and when the adjacent angles... ## The Elements of Euclid for the Use of Schools and Colleges: Comprising the ...

Euclid, Isaac Todhunter - Euclid's Elements - 1883 - 426 pages
...Wherefore, the angle &c. QED EUCLID'S ELEMENTS. COROLLARY. From the demonstration it is manifest that if one angle of a triangle be equal to the other two, it is a right angle. For the angle adjacent to it is equal to the same two angles ; [I. 32. and when the adjacent angles... ## Questions and exercises in elementary mathematics

Palaestra Oxoniensis - 1884 - 204 pages
...in one point. (4) There can be but one straight line which touches a circle in the same point. (5) If one angle of a triangle be equal to the other two, it is a right angle. (в) If from a point without a circle there be drawn two straight lines cutting it, the rectangles... ## The Harpur Euclid: An Edition of Euclid's Elements

Edward Mann Langley, W. Seys Phillips - 1890 - 538 pages
...|. major conj. L AEC at the centre, ... L ADC > a rt. L. COROLLARY.— From this it is manifest that if one angle of a triangle be equal to the other two it is a right angle. Note that III. 31 (1) and the above Corollary might have been inserted immediately after I. 32. Note... ## Books 3-9

Euclid - Mathematics, Greek - 1908 - 456 pages
...an interpolation of date later than Theon. It is to this effect : " From this it is manifest that, if one angle of a triangle be equal to the other two, the first angle is right because the exterior angle to it is also equal to the same angles, and if... 