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 4
... propositions of the fifth Book than those of any other of the Elements . In the second Book , also , some algebraic signs have been introduced , for the sake of representing more readily the addition and subtraction of the rectangles on ...
... propositions of the fifth Book than those of any other of the Elements . In the second Book , also , some algebraic signs have been introduced , for the sake of representing more readily the addition and subtraction of the rectangles on ...
Page 5
... proposition , requiring no formal demonstration to prove the truth of it ; but is received and assented to as soon as mentioned . Such as , the whole of any thing is greater than a part of it ; or , the whole is equal to all its parts ...
... proposition , requiring no formal demonstration to prove the truth of it ; but is received and assented to as soon as mentioned . Such as , the whole of any thing is greater than a part of it ; or , the whole is equal to all its parts ...
Page 6
... proposition to be true , by proving that some absurdity would necessarily follow if the proposition advanced were false . This is sometimes called Reductio ad Absurdum ; because it shows the absurdity and falsehood of all suppositions ...
... proposition to be true , by proving that some absurdity would necessarily follow if the proposition advanced were false . This is sometimes called Reductio ad Absurdum ; because it shows the absurdity and falsehood of all suppositions ...
Page 7
... proposition and the Book in which it has been announced or de- monstrated . The expression ( 15. 1. ) denotes the fifteenth proposition , first book , and so on . In like manner , ( 3. Ax . ) designates the third axiom ; ( 2. Post ...
... proposition and the Book in which it has been announced or de- monstrated . The expression ( 15. 1. ) denotes the fifteenth proposition , first book , and so on . In like manner , ( 3. Ax . ) designates the third axiom ; ( 2. Post ...
Page 11
... right angles are equal to one another . 11. " Two straight lines which intersect one another , cannot be both pa- " rallel to the same straight line . " 1 PROPOSITION I. PROBLEM . To describe an equilateral triangle OF GEOMETRY . BOOK I.
... right angles are equal to one another . 11. " Two straight lines which intersect one another , cannot be both pa- " rallel to the same straight line . " 1 PROPOSITION I. PROBLEM . To describe an equilateral triangle OF GEOMETRY . BOOK I.
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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 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 rectilineal given straight line greater Hence hypotenuse inscribed join less Let ABC Let the straight magnitudes meet opposite angle parallel parallelogram parallelopiped perpendicular polygon prism PROB PROP proportional proposition quadrilateral radius ratio rectangle contained rectilineal figure remaining angle right angled triangle SCHOLIUM segment semicircle shewn side BC sine solid angle solid parallelopiped spherical angle spherical triangle square straight line BC THEOR touches the circle triangle ABC triangle DEF wherefore
Popular passages
Page 51 - If a straight line be divided into two equal parts, and also into two unequal parts; the rectangle contained by the unequal parts, together with the square of the line between the points of section, is equal to the square of half the line.
Page 29 - Straight lines which are parallel to the same straight line are parallel to one another. Triangles and Rectilinear Figures. The sum of the angles of a triangle is equal to two right angles.
Page 12 - To draw a straight line through a given point parallel to a given straight line. Let A be the given point, and BC the given straight line.
Page 11 - 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 72 - To draw a straight line from a given point, either without or in the circumference, which shall touch a given circle. First, let A be a given point without the given circle BCD : it is required to draw a straight line from A which shall touch the circle.
Page 84 - If from any point without a circle two straight lines be drawn, one of which cuts the circle, and the other touches it ; the rectangle contained by the whole line which cuts the circle, and the part of it without the circle, shall be equal to the square of the line which touches it.
Page 80 - 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 22 - Any two sides of a triangle are together greater than the third side.
Page 53 - If a straight line be divided into any two parts, four times the rectangle contained by the whole line, and one of the parts, together with the square of the other part, is equal to the square of the straight line which is made up of the whole and that part.
Page 35 - Parallelograms upon the same base and between the same parallels, are equal to one another.