Elements of Geometry: Containing the First Six Books of Euclid, with a Supplement on the Quadrature of the Circle, and the Geometry of Solids : to which are Added, Elements of Plane and Spherical Trigonometry |
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Page viii
... drawn , or any figure to be constructed the manner of do- ing which he has not previously explained . Now , the only use of this rule is to prevent the admission of impos- sible or contradictory suppositions , which , no doubt , might ...
... drawn , or any figure to be constructed the manner of do- ing which he has not previously explained . Now , the only use of this rule is to prevent the admission of impos- sible or contradictory suppositions , which , no doubt , might ...
Page 15
... drawn from a cer- tain point within the figure to the circumference , are equal to one another . XII . And this point is called the centre of the circle . XIII . A diameter of a circle is a straight line drawn through the centre , and ...
... drawn from a cer- tain point within the figure to the circumference , are equal to one another . XII . And this point is called the centre of the circle . XIII . A diameter of a circle is a straight line drawn through the centre , and ...
Page 18
... draw the straight lines ( 1. Post . ) CA , CB to the points A , B ; ABC is an equilateral triangle . D A C Because ... draw a straight line equal to a given straight line . Let A be the given point , and BC the given straight line ; it ...
... draw the straight lines ( 1. Post . ) CA , CB to the points A , B ; ABC is an equilateral triangle . D A C Because ... draw a straight line equal to a given straight line . Let A be the given point , and BC the given straight line ; it ...
Page 19
... drawn equal to the given straight line BC . Which was to be done . PROP . III . PROB . From the greater of two given ... draw ( 2. 1. ) the straight line AD equal to C ; and from the centre A , and at the distance AD , describe ( 8. Post ) ...
... drawn equal to the given straight line BC . Which was to be done . PROP . III . PROB . From the greater of two given ... draw ( 2. 1. ) the straight line AD equal to C ; and from the centre A , and at the distance AD , describe ( 8. Post ) ...
Page 24
... draw a straight line from the point C at right angles to AB . Take any point D in AC , and ( 8. 1. ) make CE equal to CD , and upon DE describe ( 1. 1. ) the equilateral triangle DFE , and join FC ; the straight line FC , drawn from the ...
... draw a straight line from the point C at right angles to AB . Take any point D in AC , and ( 8. 1. ) make CE equal to CD , and upon DE describe ( 1. 1. ) the equilateral triangle DFE , and join FC ; the straight line FC , drawn from the ...
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Common terms and phrases
ABC is equal ABCD adjacent angles altitude angle ABC angle ACB angle BAC angle EDF arch AC base BC bisected centre circle ABC circumference cosine cylinder demonstrated diameter draw equal and similar equal angles equiangular equilateral equilateral polygon equimultiples Euclid exterior angle fore four right angles given straight line greater hypotenuse inscribed join less Let ABC Let the straight line BC meet multiple opposite angle parallel parallelogram perpendicular polygon prism PROB produced proportionals proposition Q. E. D. COR Q. E. D. PROP radius ratio rectangle contained rectilineal figure remaining angle segment semicircle side BC sine solid angle solid parallelopipeds spherical angle spherical triangle straight line AC THEOR third touches the circle triangle ABC triangle DEF wherefore
Popular passages
Page 125 - 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 39 - 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.
Page 41 - Parallelograms upon the same base and between the same parallels, are equal to one another.
Page 19 - BG; and things that are equal to the same are equal to one another; therefore the straight line AL is equal to BC. Wherefore from the given point A a straight line AL has been drawn equal to the given straight line BC.
Page 145 - If two triangles which have two sides of the one proportional to two sides of the other, be joined at one angle, so as to have their homologous sides parallel to one another ; the remaining sides shall be in a straight line. Let ABC, DCE be two triangles which have the two sides BA, AC proportional to the two CD, DE, viz.
Page 30 - If, from the ends of the side of a triangle, there be drawn two straight lines to a point within the triangle, these shall be less than, the other two sides of the triangle, but shall contain a greater angle.
Page 136 - FGL, have an angle in one equal to an angle in the other, and their sides about these equal angles proportionals ; the triangle ABE is equiangular (6.
Page 51 - 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 20 - DEF, and be equal to it ; and the other angles of the one shall coincide with the remaining angles of the other and be equal to them, viz. the angle ABC to the angle DEF, and the angle ACB to DFE.
Page 55 - If a straight line be divided into two equal, and also into two unequal parts ; the squares on the two unequal parts are together double of the square on half the line, and of the square on the line between the points of section.