An essay on mechanical geometry, explanatory of a set of models1796 |
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Page 2
... extreme points . 4. But , if the point in motion be con- tinually changing its direction , it then defcribes a crooked line , and is named a F. 2. Curve . Note , For the future , whenever we use the term a line , we mean a right line ...
... extreme points . 4. But , if the point in motion be con- tinually changing its direction , it then defcribes a crooked line , and is named a F. 2. Curve . Note , For the future , whenever we use the term a line , we mean a right line ...
Page 77
... extremes is equal to the product of the means . 16 E. 6 , or 6 D. 4 . Thus , as 6 : 2 :: 12 : 4 , by Definition 4 . Here the product of the extremes is 6X4 24 ; and 2X12 , the product of the means , Or generally , if a : b :: c : d , is ...
... extremes is equal to the product of the means . 16 E. 6 , or 6 D. 4 . Thus , as 6 : 2 :: 12 : 4 , by Definition 4 . Here the product of the extremes is 6X4 24 ; and 2X12 , the product of the means , Or generally , if a : b :: c : d , is ...
Page 78
... extremes aXd , equal to the product of the means bXc ; these four numbers are proportional , that is , as a : b :: ctd . Euclid and other Geometricians . fre- quently make use of proportions , which they quote by the terms , by ...
... extremes aXd , equal to the product of the means bXc ; these four numbers are proportional , that is , as a : b :: ctd . Euclid and other Geometricians . fre- quently make use of proportions , which they quote by the terms , by ...
Page 79
... extremes is 6 × 4 = 24 ; and of the means , 12X2 = 24 , also ; or a × d = cXb : · . · they are alternately proportional ; that is , as 6:12 :: 2 : 4 , as is expreffed in the Theorem ; or generally , as a : c :: b : d . THEOREM 5. ( 18E ...
... extremes is 6 × 4 = 24 ; and of the means , 12X2 = 24 , also ; or a × d = cXb : · . · they are alternately proportional ; that is , as 6:12 :: 2 : 4 , as is expreffed in the Theorem ; or generally , as a : c :: b : d . THEOREM 5. ( 18E ...
Page 80
... extremes 4X416 ; and the pro- duct of the means 2X8 is also = 16 ; .. 6-2 : 2 :: 12 4 : 4 ; or generally , as a - b : b :: c - d : d ; as in the Theorem . THEOREM7 . ( 15 D. 4. ) If four quantities are proportional , they will also be ...
... extremes 4X416 ; and the pro- duct of the means 2X8 is also = 16 ; .. 6-2 : 2 :: 12 4 : 4 ; or generally , as a - b : b :: c - d : d ; as in the Theorem . THEOREM7 . ( 15 D. 4. ) If four quantities are proportional , they will also be ...
Other editions - View all
An Essay on Mechanical Geometry, Explanatory of a Set of Models Benjamin Donne No preview available - 2019 |
An Essay on Mechanical Geometry, Explanatory of a Set of Models Benjamin Donne No preview available - 2016 |
Common terms and phrases
180 degrees alfo alſo Analemma angle ACD arithmetic arithmetical mean bafe baſe bifect Book breadth Briſtol called circle circumfcribing compaffes conceived cone confequently contained Corollary croffing cylinder demonftrations deſcribe diameter diſtance divided effay Euclid exactly expreffed faid fame number femicircle fhall fhewn fhould fides fignifies figure fimilar fmall folid fome four numbers fquare feet fruftum ftands ftraight fubtract fufficiently furface gallons geometrical mean Geometricians Geometry globe height Hence inftance interfect large cube length manifeft meaſure multiply half muſt number of degrees number of feet numbers are proportional oppofite orem parallel lines parallel ruler parallelogram perpendicular planes pofition pole prefent priſm PROBLEM propofitions purpoſe pyramid radius reaſon rectangle regular polygon repreſent reſpect rhombus right angles right line ſcheme Scholium ſet ſhadow ſhall ſquare Theorem theſe Thomas Beddoes thoſe three angles triangle ABC whole yards
Popular passages
Page 4 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.
Page 11 - Magnitudes which coincide with one another, that is, which exactly fill the same space, are equal to one another.
Page 23 - 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 24 - If two triangles have the three sides of the one equal to the three sides of the other, each to each, the triangles are congruent.
Page 12 - ... the three angles of a triangle are together equal to two right angles, although it is not known to all.
Page 37 - A right circular cone is often called a cone of revolution, because it can be generated by the revolution of a right-angled triangle about one of its shorter sides.
Page 10 - POSTULATES. 1. 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 65 - Multiply half the circumference by half the diameter, and the product will be the area. Or, divide the product of the whole circumference and diameter -by 4, and the quotient will be the area. 2. Multiply the square of the diameter by .7854, and the product will be the area.
Page 84 - ... reafonable creatures •, for though we all call ourfelves fo, becaufe we are born to it if we pleafe, yet we may truly fay Nature gives us but the...
Page 40 - SIMILAR cones and cylinders have to one another the triplicate ratio of that which the diameters of their bases have...