Elements of Geometry and Trigonometry |
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Page 10
... perpendicular to CD . 11. Every angle BAC , less than a right angle , is an acute angle ; and every angle DEF , greater than a right angle , is an obtuse angle . E 12. Two lines are said to be parallel , when being situated in the same ...
... perpendicular to CD . 11. Every angle BAC , less than a right angle , is an acute angle ; and every angle DEF , greater than a right angle , is an obtuse angle . E 12. Two lines are said to be parallel , when being situated in the same ...
Page 14
... perpendicular to AB , reciprocally , AB will be perpendicu- lar to DE . For , since DE is perpendicular to AB , the A angle ACD must be equal to its adjacent an- gle DCB , and both of them must be right angles ( Def . 10. ) . But since ...
... perpendicular to AB , reciprocally , AB will be perpendicu- lar to DE . For , since DE is perpendicular to AB , the A angle ACD must be equal to its adjacent an- gle DCB , and both of them must be right angles ( Def . 10. ) . But since ...
Page 20
... perpendicular to the base , and divides the angle at the vertex into two equal parts . In a triangle which is not isosceles , any side may be assumed indifferently as the base ; and the vertex is , in that case , the vertex of the ...
... perpendicular to the base , and divides the angle at the vertex into two equal parts . In a triangle which is not isosceles , any side may be assumed indifferently as the base ; and the vertex is , in that case , the vertex of the ...
Page 22
... perpendicular be let fall on the line , and oblique lines be drawn to different points : 1st , The perpendicular will be shorter than any oblique line . 2d , Any two oblique lines , drawn on different sides of the perpen- dicular ...
... perpendicular be let fall on the line , and oblique lines be drawn to different points : 1st , The perpendicular will be shorter than any oblique line . 2d , Any two oblique lines , drawn on different sides of the perpen- dicular ...
Page 23
... perpendicular , and AD , AC , AE , the oblique lines . Produce the perpendicular AB till BF is equal to AB , and draw FC , FD . First . The triangle BCF , is equal to the triangle BCA , for they have the right angle CBF CBA , the side ...
... perpendicular , and AD , AC , AE , the oblique lines . Produce the perpendicular AB till BF is equal to AB , and draw FC , FD . First . The triangle BCF , is equal to the triangle BCA , for they have the right angle CBF CBA , the side ...
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Common terms and phrases
adjacent altitude angle ACB ar.-comp base multiplied bisect Book VII centre chord circ circumference circumscribed common cone consequently convex surface cosine Cotang cylinder diagonal diameter dicular distance divided draw drawn equal angles equally distant equations equivalent feet figure find the area formed four right angles frustum given angle given line greater homologous sides hypothenuse inscribed circle inscribed polygon intersection less Let ABC logarithm measured by half number of sides opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular plane MN polyedron polygon ABCDE PROBLEM proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABCDE Scholium secant segment side BC similar sine slant height solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex
Popular passages
Page 213 - The circumference of every circle is supposed to be divided into 360 equal parts called degrees, and each degree into 60 equal parts called minutes, and each minute into 60 equal parts called seconds, and these into thirds, fourths, &c.
Page 19 - 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 233 - It is, indeed, evident, that the negative characteristic will always be one greater than the number of ciphers between the decimal point and the first significant figure.
Page 241 - In every plane triangle, the sum of two sides is to their difference as the tangent of half the sum of the angles opposite those sides is to the tangent of half their difference.
Page 168 - The radius of a sphere is a straight line drawn from the centre to any point of the surface ; the diameter or axis is a line passing through this centre, and terminated on both sides by the surface.
Page 18 - America, but know that we are alive, that two and two make four, and that the sum of any two sides of a triangle is greater than the third side.
Page 155 - AG, AK. The two solids AG, AQ having the same base AEHD, are to each other as their altitudes AB, AO. In like manner, the two solids AQ, AK having the same base AOLE, are to each other as their altitudes AD, AM. Hence we have the two proportions sol.
Page 16 - If two triangles have two sides and the included angle of the one, equal to two sides and the included angle of the other, each to each, the two triangles will be equal in all their parts." Axiom 1. "Things which are equal to the same thing, are equal to each other.
Page 32 - ... is equal to twice as many right angles as the polygon
Page 287 - How many square feet are there in the convex surface of the frustum of a square pyramid, whose slant height is 10 feet, each side of the lower base 3 feet 4 inches, and each side of the upper base 2 feet 2 inches ? Ans.