## The Elements of Euclid; viz. the first six books, together with the eleventh and twelfth. Also the book of Euclid's Data. By R. Simson. To which is added, A treatise on the construction of the trigonometrical canon [by J. Christison] and A concise account of logarithms [by A. Robertson].1814 |

### From inside the book

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**ABC**shall be an equilateral**triangle**. с Because the point A is the centre of the circle BCD , AC is equal to AB ; and because the point B is the centre 15 Defini- of the circle ACE , BC is equal to BA : But it has been tion . proved ... Page 9

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**triangle ABC**to the triangle DEF ; and the other angles to which the equal sides B are opposite , shall be CE equal each to each , viz . the angle ABC to the angle DEF , and the angle ACB to DFE . Book 1 . { For , if the**triangle ABC**be ... Page 10

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**ABC**shall be equal to the angle ACB , and the angle CBD to the angle BCE . In BD take any point F , and from AE the greater , cut 3. 1. off AG equal a to AF , the less , and ...**ABC**be a**triangle**having the angle**ABC**equal 10 THE ELEMENTS. Page 12

... triangle ACD , the angles ECD , FDC upon the other side of the base CD are 5 ... ABC , DEF be two triangles , having the two sides AB , AC , equal to the two ...

... triangle ACD , the angles ECD , FDC upon the other side of the base CD are 5 ... ABC , DEF be two triangles , having the two sides AB , AC , equal to the two ...

**triangle ABC**be applied to DEF , so that B E the point B be on E , and the ... Page 13

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**triangles**that have their sides which are terminated in one extremity of the ...**triangle**DEF ; then join AF ; the straight line AF bisects the an- gle BAC ...**ABC**, and bi- 1. 1 . seeth the angle ACB by the straight line CD . AB is cut ...### Other editions - View all

### Common terms and phrases

ABC is given AC is equal altitude angle ABC angle BAC base BC bisected BOOK XI centre circle ABCD circumference common logarithm cone cylinder demonstrated described diameter drawn equal angles equiangular equimultiples Euclid excess fore given angle given in magnitude given in position given in species given magnitude given ratio given straight line gnomon greater join less Let ABC logarithm meet multiple opposite parallel parallelogram AC perpendicular point F polygon prism proportionals proposition pyramid Q. E. D. PROP radius rectangle CB rectangle contained rectilineal figure remaining angle right angles segment side BC similar sine solid angle solid parallelopipeds square of AC straight line AB straight line BC tangent THEOR third triangle ABC triplicate ratio vertex wherefore

### Popular passages

Page 3-7 - 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 16 - Any two sides of a triangle are together greater than the third side.

Page 26 - 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 16 - If, from the ends of the 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. Let...

Page 304 - Again ; the mathematical postulate, that " things which are equal to the same are equal to one another," is similar to the form of the syllogism in logic, which unites things agreeing in the middle term.

Page 4 - DL is equal to DG, and DA, DB, parts of them, are equal ; therefore the remainder AL is equal to the remainder (3. Ax.) BG : But it has been shewn that BC is equal to BG ; wherefore AL and BC are each of them equal to BG ; and things that are equal to the same are equal to one another ; therefore the straight line AL is equal to BC.

Page 147 - 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 3-16 - 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.

Page 159 - SIMILAR triangles are to one another in the duplicate ratio of their homologous sides.