Elements of Geometry: Containing the First Six Books of Euclid, with a Supplement of the Quadrature of the Circle and the Geometry of Solids |
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Page 5
... equal to one another , but all its sides are not equal , nor its angles right angles . XXIX . All other four sided figures besides these are called trape- ziums . Book I. XXX . Parallel straight lines are such as OF GEOMETRY . 5 XXVI. ...
... equal to one another , but all its sides are not equal , nor its angles right angles . XXIX . All other four sided figures besides these are called trape- ziums . Book I. XXX . Parallel straight lines are such as OF GEOMETRY . 5 XXVI. ...
Page 6
... Parallel straight lines are such as are in the same plane , and which , being produced ever so far both ways , do not meet . POSTULATES . I. LET it be granted that a straight line may be drawn from any one point to any other point . II ...
... Parallel straight lines are such as are in the same plane , and which , being produced ever so far both ways , do not meet . POSTULATES . I. LET it be granted that a straight line may be drawn from any one point to any other point . II ...
Page 7
... X. All right angles are equal to one another . " Two straight lines , which intersect one another , cannot be " both parallel to the same straight line . " Book I. Book I. late . PROPOSITION I. PROBLEM . TO describe OF GEOMETRY .
... X. All right angles are equal to one another . " Two straight lines , which intersect one another , cannot be " both parallel to the same straight line . " Book I. Book I. late . PROPOSITION I. PROBLEM . TO describe OF GEOMETRY .
Page 29
... parallel . Let the straight line EF , which falls upon the two straight lines AB , CD , make the alternate angles AEF , EFD equal to one another : AB is parallel to CD . 14 For , if it be not parallel , AB and CD being produced shall ...
... parallel . Let the straight line EF , which falls upon the two straight lines AB , CD , make the alternate angles AEF , EFD equal to one another : AB is parallel to CD . 14 For , if it be not parallel , AB and CD being produced shall ...
Page 30
... parallel to CD . Wherefore , if a straight line , & c . Q. E. D. See N. PROP . XXIX . THEOR . IF a straight line fall upon two parallel straight lines , it makes the alternate angles equal to one ano- ther ; and the exterior angle equal ...
... parallel to CD . Wherefore , if a straight line , & c . Q. E. D. See N. PROP . XXIX . THEOR . IF a straight line fall upon two parallel straight lines , it makes the alternate angles equal to one ano- ther ; and the exterior angle equal ...
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Common terms and phrases
ABC is equal ABCD altitude angle ABC angle ACB angle BAC angle contained angle EDF arch base BC bisected Book centre circle ABC circumference coincide cylinder definition demonstrated diameter draw drawa equal angles equiangular equilateral polygon equimultiples Euclid exterior angle fore four right angles given circle given straight line greater inscribed interior and opposite join less Let ABC Let the straight meet multiple opposite angle parallelogram perpendicular point F polygon prism PROB produced proportional proposition pyramid Q. E. D. COR Q. E. D. PROP ratio rectangle contained rectilineal figure remaining angle segment solid angle solid parallelepipeds straight line AB straight line AC Suppl THEOR third touches the circle triangle ABC triangle DEF
Popular passages
Page 121 - If two triangles have two angles of the one equal to two angles of the other, each to each, and one side equal to one side, viz. either the sides adjacent to the equal...
Page 42 - TO a given straight line to apply a parallelogram, which shall be equal to a given triangle, and have one of its angles equal to a given rectilineal angle.
Page 63 - Therefore, in obtuse-angled triangles, &c. QED PROP. XIII. THEOREM. In every triangle, the square of the side subtending either of the acute angles is less than the squares of the sides containing that angle, by twice the rectangle contained by either of these sides, and the straight line intercepted between the perpendicular let fall upon it from the opposite angle, and the acute angle.
Page 3 - A circle is a plane figure contained by one line, which is called the circumference, and is such that all straight lines drawn from a certain point within the figure to the circumference, are equal to one another.
Page 183 - Equiangular parallelograms have to one another the ratio which is compounded of the ratios of their sides. Let AC, CF be equiangular parallelograms having the angle BCD equal to the angle ECG ; the ratio of the parallelogram AC to the parallelogram CF is the same with the ratio which is compounded •f the ratios of their sides.
Page 3 - A diameter of a circle is a straight line drawn through the centre, and terminated both ways by the circumference.
Page 291 - 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 160 - ... extremities of the base shall have the same ratio which the other sides of the triangle have to one...
Page 10 - ... shall be greater than the base of the other. Let ABC, DEF be two triangles, which have the two sides AB, AC, equal to the two DE, DF, each to each, viz.
Page 14 - Therefore, upon the same base, and on the same side of it, there cannot be two triangles that have their sides which are terminated in one extremity of the base equal to one another, and likewise those which are terminated in the other extretnity equal to one another.