 | Euclid, James Thomson - Geometry - 1837 - 410 pages
...semicircle is acute, and an angle in a segment less than a semicircle is obtuse. PROP. XXXII. THEOR. IF a straight line touch a circle, and from the point of contact a straight line be drawn dividing the circle into two segments ; the angles made by this line with the tangent are... | |
 | John Playfair - Euclid's Elements - 1837 - 332 pages
...perpendicular to DE ; FC is therefore perpendicular to DE. 74 N PROP. XIX. THEOR. If a. straight linf touch a circle, and from the point of contact a straight line be drawn at right angles to the touching line, the centre of the circle is in that line. Let the straight... | |
 | Euclides - 1838 - 264 pages
...supposed to have been subjoined, not by Euclid, but by some one of the early editors. PROP. XIX. THEOR. If a straight line touch a circle, and from the point of contact a straight line be drawn at right angles to the touching line, the centre of the circle shall be in that line. Let... | |
 | Euclides - 1840 - 82 pages
...segment less than a semicircle, is an obtuse angle. PROP. XXXII. THEOR. If a straight line touches a circle, and from the point of contact a straight line is drawn, cutting the circle, the angles made by this cutting line with the tangent are equal to the angles in... | |
 | Euclides - Geometry - 1841 - 378 pages
...two; and when the adjacent angles are equal, they are right* angles. »iol>ef. PROP. XXXII. THEOR. If a straight line touch a circle, and from the point of contact a straight line be drawn cutting the circle, the angles which this line makes with the line touching the circle, shall... | |
 | John Playfair - Euclid's Elements - 1842 - 332 pages
...other line but FC can be perpendicular to DE ; FC is therefore perpendicular to DE. PROP. XIX. THEOR. If a straight line touch a circle, and from the point of contact a straight line be drawn at right angles to the touching line, the centre of the circle is in that line. Let the straight... | |
 | Education - 1844 - 688 pages
...opposite angles of any quadrilateral inscribed in a circle, are together equal to two right angles. 11. If a straight line touch a circle, and from the point of contact a straight line be drawn cutting the circle ; the angles which this line makes with the touching line, shall be equal... | |
 | John Playfair - Euclid's Elements - 1844 - 338 pages
...be perpendicular to DE ; FC is therefore perpendicular to DE. PROP. XIX. THEOR. If a straight lino touch a circle, and from the point of contact a straight line be drawn at right angles to the touching line, the centre of the circle is in that line, Let the straight... | |
 | Euclid - Geometry - 1845 - 218 pages
...that is, FC is perpendicular to DE. Therefore, if a straight line, &c. QED PROPOSITION XIX. THEOB. — If a straight line touch a circle, and from the point of contact a straight line be drawn at right angles to the touching line, the centre of the circle shall be in that line. Let... | |
 | Euclid, James Thomson - Geometry - 1845 - 382 pages
...semicircle is acute, and an angle ma segment less than a semicircle is obtuse. PROP. XXXII. THEOR. — If a straight line touch a circle, and from the point of contact a straight line be drawn dividing the circle into two segments ; the angles made by this line with the tangent are... | |
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If a straight line touch a circle, and from the point of contact a chord be drawn, the angles which this chord makes with the tangent are equal to the angles in the alternate segments. 
