Elements of Geometry: Containing the First Six Books of Euclid: With a Supplement ... to which are Added, Elements of Plane and Sphericale Trigonometry ... From the Last London Ed., Enl |
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Page 3
... manner , A - B + C , or A + C - B , signifies that A and C are to be added together , and that B is to be subtracted from their sum . 22. Multiplication is expressed by an oblique cross , by a point , or by simple apposition : thus , Ax ...
... manner , A - B + C , or A + C - B , signifies that A and C are to be added together , and that B is to be subtracted from their sum . 22. Multiplication is expressed by an oblique cross , by a point , or by simple apposition : thus , Ax ...
Page 20
... manner , it may be demonstrated , that no other can be in the same straight line with it but BD , which therefore is in the same straight line with CB . PROP . XV . THEOR . If two straight lines cut one another , the vertical , or ...
... manner , it may be demonstrated , that no other can be in the same straight line with it but BD , which therefore is in the same straight line with CB . PROP . XV . THEOR . If two straight lines cut one another , the vertical , or ...
Page 21
... manner , if the side BC be bisected , it may be demonstrated that the angle BCG , that is ( 15. 1. ) , the angle ACD , is greater than the angle ABC . B E F D 2 PROP . XVII . THEOR . Any two angles of a triangle are together less than ...
... manner , if the side BC be bisected , it may be demonstrated that the angle BCG , that is ( 15. 1. ) , the angle ACD , is greater than the angle ABC . B E F D 2 PROP . XVII . THEOR . Any two angles of a triangle are together less than ...
Page 22
... manner it may be demonstrated , that the sides AB , BC are greater than CA , and BC , CA greater than AB . B SCHOLIUM . C This may be demonstrated without producing any of the sides : thus , the line BC , for example , is the shortest ...
... manner it may be demonstrated , that the sides AB , BC are greater than CA , and BC , CA greater than AB . B SCHOLIUM . C This may be demonstrated without producing any of the sides : thus , the line BC , for example , is the shortest ...
Page 27
... manner it may be demonstrated that they do not meet towards A , C ; but those straight lines which meet neither way , though produced ever so far , are parallel ( 30. Def . ) A E B G C F D to one another . AB therefore is parallel to CD ...
... manner it may be demonstrated that they do not meet towards A , C ; but those straight lines which meet neither way , though produced ever so far , are parallel ( 30. Def . ) A E B G C F D to one another . AB therefore is parallel to CD ...
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Common terms and phrases
ABC is equal ABCD adjacent angles altitude angle ABC angle ACB angle BAC base BC bisected centre chord circle ABC circumference coincide cosine cylinder definition demonstrated described diameter divided draw equal and similar equal angles equiangular equilateral equilateral polygon equimultiples Euclid exterior angle fore four right angles given straight line greater Hence hypotenuse inscribed join less Let ABC magnitudes meet opposite angle parallel parallelogram parallelopiped perpendicular polygon prism PROB produced PROP proportional proposition quadrilateral radius ratio rectangle contained rectilineal figure remaining angle right angled triangle SCHOLIUM segment semicircle shewn side BC sine solid angle spherical angle spherical triangle square straight line BC THEOR third touches the circle triangle ABC triangle DEF wherefore
Popular passages
Page 3 - When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the straight line which stands on the other is called a perpendicular to it.
Page 122 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.
Page 74 - The angle in a semicircle is a right angle: the angle in a segment greater than a semicircle is less than a right angle ; and the angle in a segment less than a semicircle is greater than a right angle.
Page 44 - If a straight line be divided into any two parts, the square of the whole line is equal to the squares of the two parts, together with twice the rectangle contained by the parts.
Page 5 - Let it be granted that a straight line may be drawn from any one point to any other point. 2. That a terminated straight line may be produced to any length in a straight line. 3. And that a circle may be described from any centre, at any distance from that centre.
Page 290 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 277 - If a straight line meets two straight lines, so as to make the two interior angles on the same side of it taken together less than two right angles...
Page 143 - ... cuts the base, the rectangle contained by the sides of the triangle is equal to the rectangle contained by the segments of the base, together with the square on the straight line which bisects the angle.
Page 7 - If two triangles have two sides of the one equal to two sides of the...
Page 26 - THE straight lines which join the extremities of two equal and parallel straight lines, towards the same parts, are also themselves equal and parallel. Let AB, CD be equal and parallel straight lines, and joined towards the same parts by the straight lines AC, BD ; AC, BD are also equal and parallel.