Search Images Maps Play YouTube News Gmail Drive More »
 Books Books
If, at a point in a straight line, two other straight lines, upon the opposite sides of it, make the adjacent angles together equal to two right angles, these two straight lines shall be in one and the same straight line.
Euclid - Page 31
by Euclid, Rupert Deakin - 1903 - 164 pages

The Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclid - 1835 - 540 pages
...are together equal to two right angles. Wherefore, " when a straight line," &c. QED PROP. XIV. THEOR. If, at a point in a straight line, two other straight lines upon the opposite sides of it, make the adjacent angles, together equal to two right angles, these...

Library of Useful Knowledge: Geometry plane, solid, and spherical [by Pierce ...

Mathematics - 1835 - 684 pages
...Straight lines which pass through the same two points lie in the same straight line . . . ax. 4 (J>) If at a point in a straight line two other straight lines upon opposite sides of it make the adjacent angles together equal to two right angles, these two straight...

The Element of Geometry

John Playfair - Geometry - 1836 - 148 pages
...makes with another on the same side of it, are together equal to two right angles. PROP. II. THEOR. If, at a point in a straight line, two other straight lines on the opposite sides of it make the adjacent angles together equal to two right angles, these two straight...

The Teacher's Assistant in the "Course of Mathematics Adapted to the Method ...

Mathematics - 1836 - 488 pages
...another upon one side of it, are either two right angles, or are together equal to two right angles. XIV. If, at a point in a straight line, two other straight lines, upon the op. posite sides of it, make the adjacent angles together equal to two right angles, these...

A companion to Euclid: being a help to the understanding and remembering of ...

Euclides - Euclid's Elements - 1837 - 112 pages
...3. that Zs DBA + ABC = the two rt. Zs CBE + EBD. PROPOSITION XIV. (Argument ad absurdum). Theorem. If, at a point in a straight line, two other straight...lines shall be in one and the same straight line. Steps of the Demonstration. Suppose that BD is not in the same st. line with BC, but that BE is in...

Elements of Geometry: Containing the First Six Books of Euclid : with a ...

John Playfair - Geometry - 1837 - 332 pages
...angles DBA, ABC. PROP. XIV. THEOR. If, at a point in a straight line, two other straight lines, upon the opposite sides of it, make the adjacent angles together...equal to two right angles, these two straight lines are in one and the same straight line. At the point B in the straight line AB, let the two straight...

Lessons on Form: Or, An Introduction to Geometry, as Given in a Pestalozzian ...

Charles Reiner - Geometry - 1837 - 246 pages
...which are these interior angles. 24. If, at one point in a straight line, two other straight lines make the adjacent angles, together, equal to two right angles, these two lines are in the same straight line. SECTION III. ONE TRIANGLE. M. — State all you have learnt concerning...

The First Six and the Eleventh and Twelfth Books of Euclid's Elements: With ...

Euclid, James Thomson - Geometry - 1837 - 410 pages
...it but BD, which therefore is in the same straight line with CB. Wherefore, if at a point, &c. Cor. If, at a point in a straight line, two other straight lines meet on the opposite sides of it, and make equal angles with the parts of it on opposite sides of the...