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 10
... which has all its angles right angles , but has not all its sides equal . 27. A rhombus is that which has all its sides equal , but its angles are not right angles . ᄆᄆ 28. A rhomboid is that , which has its opposite 10 ELEMENTS .
... which has all its angles right angles , but has not all its sides equal . 27. A rhombus is that which has all its sides equal , but its angles are not right angles . ᄆᄆ 28. A rhomboid is that , which has its opposite 10 ELEMENTS .
Page 11
... opposite sides equal to one another , but all its sides are not equal , nor its angles right angles . 29. All other four sided figures besides these , are called trapeziums . 30. Parallel straight lines are such as are in the same plane ...
... opposite sides equal to one another , but all its sides are not equal , nor its angles right angles . 29. All other four sided figures besides these , are called trapeziums . 30. Parallel straight lines are such as are in the same plane ...
Page 13
... opposite . * Let ABC , DEF be two triangles which have the two sides AB , AC equal to the two sides DE , DF , each to each , viz . AB to DE , and AC to DF ; and let the angle BAC be also equal to the angle EDF : then shall A D he base ...
... opposite . * Let ABC , DEF be two triangles which have the two sides AB , AC equal to the two sides DE , DF , each to each , viz . AB to DE , and AC to DF ; and let the angle BAC be also equal to the angle EDF : then shall A D he base ...
Page 14
... opposite , shall be equal , each to each . PROP . V. THEOR . The angles at the base of an Isosceles triangle are equal to one another ; and if the equal sides be produced , the angles upon the other side of the base shall be equal . Let ...
... opposite , shall be equal , each to each . PROP . V. THEOR . The angles at the base of an Isosceles triangle are equal to one another ; and if the equal sides be produced , the angles upon the other side of the base shall be equal . Let ...
Page 15
... opposite to them , are also equal to one another . Let ABC be a triangle having the angle ABC equal to the angle ACB ; the side AB is also equal to the side AC . For , if AB be not equal to AC , one of them is greater than the other ...
... opposite to them , are also equal to one another . Let ABC be a triangle having the angle ABC equal to the angle ACB ; the side AB is also equal to the side AC . For , if AB be not equal to AC , one of them is greater than the other ...
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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 line BC magnitudes meet opposite angle parallel parallelogram parallelopiped perpendicular plane 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 spherical angle spherical triangle square straight line AC THEOR third touches the circle triangle ABC triangle DEF wherefore
Popular passages
Page 41 - 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 70 - 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 45 - Again, because the angle at B is half a right angle, and FDB a right angle, for it is equal...
Page 91 - 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 273 - If a straight line meet 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 25 - Parallelograms upon the same base and between the same parallels, are equal to one another.
Page 130 - Equiangular parallelograms have to one another the ratio which is compounded of the ratios of their sides.
Page 61 - THE diameter is the greatest straight line in a circle; and, of all others, that which is nearer to the centre is always greater than one more remote ; and the greater is nearer to the centre than the less.* Let ABCD be a circle, of which...