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 |
From inside the book
Results 1-5 of 100
Page 10
... THEOR . The angles at the base of an isosceles triangle are equal to one another : namely , those to which the equal sides are opposite . If the triangle ABC have the side AC equal to the side BC : then will the angle B be equal to the ...
... THEOR . The angles at the base of an isosceles triangle are equal to one another : namely , those to which the equal sides are opposite . If the triangle ABC have the side AC equal to the side BC : then will the angle B be equal to the ...
Page 12
... THEOR . The angles which one straight line makes with another upon one side of it , are either two right angles , or are together equal to two right angles . Let the straight line AB make with CD , upon one side of it the angles CBA ...
... THEOR . The angles which one straight line makes with another upon one side of it , are either two right angles , or are together equal to two right angles . Let the straight line AB make with CD , upon one side of it the angles CBA ...
Page 13
... THEOR . B T D If two straight lines cut one another , the vertical , or opposite angles are equal . Let the two straight lines AB , CD , cut one another in the point E : the angle AEC shall be equal to the angle DEB , and CEB to AED ...
... THEOR . B T D If two straight lines cut one another , the vertical , or opposite angles are equal . Let the two straight lines AB , CD , cut one another in the point E : the angle AEC shall be equal to the angle DEB , and CEB to AED ...
Page 14
... THEOR . Any two angles of a triangle are together less than two right angles . Let ABC be any triangle ; any two of its angles together are less than two right angles . A Produce BC to D ; and because ACD is the exterior angle of the ...
... THEOR . Any two angles of a triangle are together less than two right angles . Let ABC be any triangle ; any two of its angles together are less than two right angles . A Produce BC to D ; and because ACD is the exterior angle of the ...
Page 15
... THEOR . The greater angle of every triangle is subtended by the greater side , or has the greater side opposite to it . Let ABC be a triangle , of which the angle ABC is greater than the an- gle BCA ; the side AC is likewise greater ...
... THEOR . The greater angle of every triangle is subtended by the greater side , or has the greater side opposite to it . Let ABC be a triangle , of which the angle ABC is greater than the an- gle BCA ; the side AC is likewise greater ...
Other editions - View all
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.