 | John Playfair - 1855 - عدد الصفحات: 350
...other line but FC can be perpendicular to DE ; FC is therefore perpendicular to DE. B PROP. XIX. THEOR. If a straight line touch a circle, and from the point of contact a stimght Imt be drawn at right angles to the touching line, the centre of the circle is in that line.... | |
 | Euclid, Isaac Todhunter - 1867 - عدد الصفحات: 426
...the adjacent angles are equal, they are right angles. * [I. Definition 10. PROPOSITION 32. THEOREM. If a straight line touch a circle, and from the point of contact a straight line lie drawn cutting the circle, the angles which this line makes with the line touching the circle shall... | |
 | Euclid, Isaac Todhunter - 1867 - عدد الصفحات: 424
...FC is perpendicular to DE. Wherefore, if a straight line &c. PROPOSITION 19. THEOREM. If a ttraight 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 the straight... | |
 | Edinburgh univ - 1868 - عدد الصفحات: 336
...square of the other part. 5. The angles in the same segment of a circle are equal to one another. 6. If a straight line touch a circle, and from the point...straight line be drawn cutting the circle, the angles made by this line with the line which touches the circle shall be equal to the angles in the alternate... | |
 | Robert Potts - 1868 - عدد الصفحات: 434
...when the adjacent angles are equal, they are right angles. (I. def. 10.) PROPOSITION XXXII. THEOREM. If a, straight line touch a circle, and from the point of contact a straight line be drawn meeting the circle ; the angles which this line makes with the line touching the circle shall be equal... | |
 | Cambridge univ, exam. papers - 1870 - عدد الصفحات: 272
...the whole line thus produced, and the given line, may be equal to the square on the part produced. 3. If a straight line touch a circle, and from the point...which are in the alternate segments of the circle. A circle is inscribed in a triangle, and the points of contact joined, so as to form another triangle.... | |
 | Edinburgh univ - 1871 - عدد الصفحات: 392
...which you appeal. tained by the whole and that part together with the square of the other part. 4. If a straight line touch a circle, and from the point...straight line be drawn cutting the circle, the angles made by this line with the line which touches the circle, are equal to the angles in the alternate... | |
 | Henry William Watson - 1871 - عدد الصفحات: 320
...triangles are equal in all respects, therefore DE is equal to DF, and ADE is equal to ADF. PROPOSITION 2I. If a straight line touch a circle and from the point of contact another straight line be drawn cutting the circle, the angles which the cutting line makes with the... | |
 | Euclides, James Hamblin Smith - 1872 - عدد الصفحات: 376
...are normals to the circle at the points where they meet the circumference. PROPOSITION XIX. THEOREM. 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 must be in that line. Let the st. line... | |
 | Euclides - 1872 - عدد الصفحات: 102
...circles touched by both lines lie in two lines at right angles to each other. PROPOSITION XIX. THEOREM. If a straight line touch a circle, and from the point of contact a straight line be draicn at right angles to the touching line, the centre of the circle must be in that line. Let the... | |
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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. 
