 | Euclides - 1865 - 402 pages
...besides FC; that is, FC is perpendicular to DE. Therefore, if a straight line, &e. QED PROP. 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 shall be in that line. (References... | |
 | James Robert Christie - Mathematics - 1866 - 428 pages
...radius a, about its diameter. i • • J; >. , г.- •• . . - • I. GEOMETRY. > » •' *•"' 1. ' 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, && . 2. The sides about the equal angles... | |
 | John Playfair - Geometry - 1855 - 350 pages
...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 - Euclid's Elements - 1867 - 426 pages
...angles ; . [I. 32. and when the adjacent angles are equal, they are right angles. * [I. Definition 10. PROPOSITION 32. THEOREM. If a straight line touch...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 - Euclid's Elements - 1867 - 424 pages
...angles ; [I. 32. and when the adjacent angles are equal, they are right angles. [I. Definition 10. PROPOSITION 32. THEOREM. If a straight line touch...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... | |
 | Robert Potts - 1868 - 434 pages
...same manner it may be shewn, that no other line is perpendicular to DE besides FC, 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 center of the circle shall be in that line. Let... | |
 | Edinburgh univ - 1868 - 336 pages
...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 of contact a straight line be drawn cutting the circle, the angles made by this line with the line which touches the circle shall... | |
 | Cambridge univ, exam. papers - 1870 - 272 pages
...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 of contact a straight line be drawn cutting the circle, the angles which this line makes with the line touching the circle shall... | |
 | Edinburgh univ - 1871 - 392 pages
...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 of contact a straight line be drawn cutting the circle, the angles made by this line with the line which touches the circle, are... | |
 | Henry William Watson - Geometry - 1871 - 320 pages
...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... | |
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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. 
