## The Elements of Euclid, the parts read in the University of Cambridge [book 1-6 and parts of book 11,12] with geometrical problems, by J.W. Colenso1846 |

### From inside the book

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**fourth**of the vertical angle , and from it a line be drawn perpendicular to the base to meet the opposite side pro- duced , then the part produced , the perpendicular , and the remaining side , will form an equilateral triangle . 53 ... Page 55

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**fourth**of the triangle ACE ; and , conversely , if BD be such that AD is half of AE , then BD is parallel to CE . 82. If the sides of any quadrilateral be bisected and the points of bisection joined , the included figure is a ... Page 153

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**fourth**, when , any equimultiples whatever of the first and third being taken , and any whatever of the second and**fourth**, if the multiple of the first be equal that of the second , the multiple of the third is also equal to that of ... Page 154

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**fourth**, and the third is said to have to the**fourth**a less ratio than the first has to the second . VIII . Analogy , or proportion , is the similitude of ratios . IX . Proportion consists in three terms at least . x . When three ... Page 155

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**fourth**; as is shewn in ( 5. 16 ) : XIV . Invertendo , by inversion ; when there are four proportionals , and it is inferred , that the second is to the first as the**fourth**to the third ( 5. B ) : XV . Componendo , by composition ...### Other editions - View all

The Elements of Euclid, the Parts Read in the University of Cambridge [Book ... Euclides No preview available - 2016 |

### Common terms and phrases

ABCD adjacent angles angle ABC angle ACB angle BAC angle BCD angle EDF angle equal base BC BC is equal centre chord circle ABC circumference cuts the circle diameter double draw equal angles equal to F equiangular equilateral triangle equimultiples exterior angle fore given circle given line given point given straight line gnomon greater ratio inscribed intersection isosceles triangle less Let ABC Let the straight lines be drawn lines drawn meet multiple opposite angles opposite sides parallel to BC parallelogram pentagon perpendicular plane polygon PROB produced proportionals Q.E.D. PROP rectangle contained rectilineal figure remaining angle right angles right-angled triangle segment semicircle shew shewn square of AC straight line &c straight line AB THEOR touches the circle triangle ABC twice the rectangle Wherefore

### Popular passages

Page 42 - To a given straight line to apply a parallelogram, which shall be equal to a given triangle, and have one of its angles equal to a given rectilineal angle.

Page 4 - Let it be granted that a straight line may be drawn from any one point to any other point.

Page 33 - F, which is the common vertex of the triangles: that is », together with four right angles. Therefore all the angles of the figure, together with four right angles are equal to twice as many right angles as the figure has sides.

Page 62 - 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 22 - If from the ends of a side of a triangle, there be drawn two straight lines to a point within the triangle, these shall be less than the other two sides of the triangle, but shall contain a greater angle.

Page 58 - If there be two straight lines, one of which is divided into any number of parts, the rectangle contained by the two straight lines is equal to the rectangles contained by the undivided line, and the several parts of the divided line.

Page 146 - ... may be demonstrated from what has been said of the pentagon : and likewise a circle may be inscribed in a given equilateral and equiangular hexagon, and circumscribed about it, by a method like to that used for the pentagon.

Page 194 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.

Page 2 - 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 : 16.

Page 69 - To divide a given straight line into two parts, so that the rectangle contained by the whole, and one of the parts, may be equal to the square of the other part.