 | Euclid, John Playfair - Euclid's Elements - 1846 - 334 pages
...perpendicular to DE ; FC is therefore perpendicular to DE. ELEMENTS 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 line... | |
 | Euclides - 1848 - 52 pages
...or in the circumference, which shall touch a given circle. PROP. XVIII. THEOREM. 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. PROP. XX. THEOREM.... | |
 | Euclid, Thomas Tate - 1849 - 120 pages
...perpendicular to DE. Therefore, if D a straight line, &c. QED PROP. XIX. THEOR. If a straight line touches 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... | |
 | Euclid, John Playfair - Geometry - 1853 - 336 pages
...to the same two ; and when the adjacent angles are equal, they are right angles. PROP. XXXII. THEOR. If a straight line touch a circle, and from the point...line be drawn cutting the circle, the angles made by thin line with the line which touches the circle, shall be equal to the angles in the alternate segments... | |
 | Euclides - 1853 - 146 pages
...FC; that is 5. FC is perpendicular to DE. Therefore, if a straight line, &c. 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. Let the straight... | |
 | Royal Military Academy, Woolwich - Mathematics - 1853 - 400 pages
...that is, FC is perpendicular to DE. Therefore, if a straight line, etc. QED PROPOSITION 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 the straight... | |
 | Euclides - Geometry - 1853 - 334 pages
...touching lines are right angles, and therefore equal : which is impossible (Az. 9). PBOP. XIX. THEOE. If a straight line touch a circle, and from the point of contact a straight line be drawn at right angles to it : then the centre of the circle shall be in that line. Let DE touch the circle... | |
 | Euclid - Geometry - 1853 - 176 pages
...part ff the circumference for its base as an angle at the circumference. If a straight line touches a circle, and from the point of contact a straight line be drawn cutting the circle. They shall stand upon equal parts of the circumference, whether they be at the center or the circumfer... | |
 | Euclides - Geometry - 1853 - 176 pages
...e. Therefore, if a straight line, &c. QED PROPOSITION XIX. — THEOREM. If a straight line touches 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... | |
 | William Somerville Orr - Science - 1854 - 534 pages
...here only to avoid interruption in the numbering of the propositions. PROPOSITION XIX.— THEOREM. If a straight line touch a circle, and from the point of contact a straight line be draw» at right angles to the touching line, the centre of the circle shall be in that. lim. PROPOSITION... | |
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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 touching the circle, shall be equal to the angles which are in the alternate segments of the circle. 
