## 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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**pyramid**is a solid figure contained by planes that are constituted betwixt one plane and one point above it în which they meet . XIII . A prism is a solid figure contained by plane figures , of which two that are opposite are equal ... Page 249

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**pyramid**. Ꭰ Let there be a**pyramid**of which the base is the triangle ABC and its vertex the point D : The**pyramid**ABCD may be divided into two equal and similar**pyramids**having triangular bases , and similar to the whole ; and into two ... Page 250

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**pyramid**, the base of which is the triangle KHL , and vertex the point D. And because HK is parallel to AB , a side ...**pyramid**of which the base is the 2. 11. & triangle ABC , and vertex the point D , is therefore similari Def . 11. to ... Page 251

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**pyramid**of which the base is the triangle EBF , and vertex the point K : But this py- ramid is equal to the**pyramid**the base of which is the C. 11 . triangle AEG , and vertex the point H ; because they are contained by equal and similar ... Page 252

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**pyramids**of the same altitude , upon triangular bases , and each of them be divided into two equal**pyramids**similar to the whole**pyramid**, and also into two equal prisms ; and if each of these**pyramids**be divided in the same manner as ...### 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.