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
... bisected , or di- vided into two equal parts by the line CD , mak- ing the angle ACD equal to the angle BCD . Then ... bisecting the vertical angle of an isosceles tri- angle is perpendicular to its base , and divides that base into two ...
... bisected , or di- vided into two equal parts by the line CD , mak- ing the angle ACD equal to the angle BCD . Then ... bisecting the vertical angle of an isosceles tri- angle is perpendicular to its base , and divides that base into two ...
Page 14
... bisected , it may be demonstrated that the angle BCG , that is ( 8. 1. ) the angle ACD , is greater than the angle ABC . PROP . X. THEOR . Any two angles of a triangle are together less than two right angles . Let ABC be any triangle ...
... bisected , it may be demonstrated that the angle BCG , that is ( 8. 1. ) the angle ACD , is greater than the angle ABC . PROP . X. THEOR . Any two angles of a triangle are together less than two right angles . Let ABC be any triangle ...
Page 33
... bisect a given rectilineal angle , that is , to divide it into two equal angles . A Let BAC be the given rectilineal ... bisected by the straight line AF . SCHOLIUM . B By the same construction , each of the halves BAF , CAF , may be ...
... bisect a given rectilineal angle , that is , to divide it into two equal angles . A Let BAC be the given rectilineal ... bisected by the straight line AF . SCHOLIUM . B By the same construction , each of the halves BAF , CAF , may be ...
Page 34
... bisect a given finite straight line , that is , to divide it into two equal parts . Let AB be the given straight line ; it is required to divide it into two equal parts . Describe ( Prob . 1. ) upon it an equilateral triangle ABC , and ...
... bisect a given finite straight line , that is , to divide it into two equal parts . Let AB be the given straight line ; it is required to divide it into two equal parts . Describe ( Prob . 1. ) upon it an equilateral triangle ABC , and ...
Page 35
... bisect ( Prob . 5. ) FG in H , and join CF , CH , CG ; the straight line CH , drawn from the given point C , is perpendicular to the given straight line AB . C E A F H G B D Because FH is equal to HG , and HC common to the two triangles ...
... bisect ( Prob . 5. ) FG in H , and join CF , CH , CG ; the straight line CH , drawn from the given point C , is perpendicular to the given straight line AB . C E A F H G B D Because FH is equal to HG , and HC common to the two triangles ...
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Common terms and phrases
ABC is equal ABCD adjacent angles altitude angle ABC angle ACB angle BAC angles equal arc AC base BC bisected centre chord circle ABC circumference cosine cylinder demonstrated diameter divided draw Prob equal and similar equal angles equiangular equilateral equilateral polygon equimultiples Euclid exterior angle fore four right angles given straight line greater Hence hypotenuse inscribed join less Let ABC Let the straight magnitudes meet multiple opposite angle parallel parallelogram parallelopiped perpendicular plane polygon prism PROP proposition quadrilateral radius ratio rectangle contained rectilineal figure remaining angle SCHOLIUM segment semicircle shewn side BC sine solid angle solid parallelopiped spherical angle spherical triangle square straight line BC THEOR third touches the circle triangle ABC triangle DEF wherefore
Popular passages
Page 46 - If a straight line be divided into any two parts, the square of the whole line is equal to the squares of the two parts, together with twice the rectangle contained by the parts.
Page 39 - To describe a parallelogram that shall be equal to a given triangle, and have one of its angles equal to a given rectilineal angle.
Page 47 - 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 on the line between the points of section, is equal to the square on half the line.
Page 25 - THE straight lines which join the extremities of two equal and parallel straight lines, towards the same parts, are also themselves equal and parallel. Let AB, CD be equal and parallel straight lines, and joined towards the same parts by the straight lines AC, BD ; AC, BD are also equal and parallel.
Page 5 - 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 75 - 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 95 - 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 294 - 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 52 - In obtuse-angled triangles, if a perpendicular be drawn from either of the acute angles to the opposite side produced, the square of the side subtending the obtuse angle, is greater than the squares of the sides containing the obtuse angle, by twice the rectangle contained by the side upon which, when produced, the perpendicular falls, and the straight line intercepted without the triangle, between the perpendicular and the obtuse angle. Let ABC be an obtuse-angled triangle, having the obtuse angle...
Page 134 - Equiangular parallelograms have to one another the ratio which is compounded of the ratios of their sides.