Euclid, book i., propositions i. to xxvi., with exercises and alternative proofs [by T. Dalton].1877 |
From inside the book
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Page 2
... Common Notions , which are self - evident truths , that is , truths which are so simple as not to require proof , and they are for the most part concerned with the equality of magnitudes . Starting from these , Euclid proceeds to deduce ...
... Common Notions , which are self - evident truths , that is , truths which are so simple as not to require proof , and they are for the most part concerned with the equality of magnitudes . Starting from these , Euclid proceeds to deduce ...
Page 14
... common to the triangles AFC , AGB ; therefore the base FC is equal to the base GB , ( prop . 4 ) and the triangle AFC is equal to the triangle AGB , and the remaining angles of the one to the remaining angles of the other , each to each ...
... common to the triangles AFC , AGB ; therefore the base FC is equal to the base GB , ( prop . 4 ) and the triangle AFC is equal to the triangle AGB , and the remaining angles of the one to the remaining angles of the other , each to each ...
Page 17
... common to both triangles , and the contained angle DBC is equal to the contained angle ACB , therefore the triangle DBC is equal to the triangle ACB : ( prop . 4 ) that is , the less triangle is equal to the greater , which is absurd ...
... common to both triangles , and the contained angle DBC is equal to the contained angle ACB , therefore the triangle DBC is equal to the triangle ACB : ( prop . 4 ) that is , the less triangle is equal to the greater , which is absurd ...
Page 25
... common to the triangles , and the base DF is equal to the base EF , therefore the angle DCF is equal to the angle ECF ; ( prop . 8 ) and they are adjacent angles : but " when a straight line standing on another straight line makes the ...
... common to the triangles , and the base DF is equal to the base EF , therefore the angle DCF is equal to the angle ECF ; ( prop . 8 ) and they are adjacent angles : but " when a straight line standing on another straight line makes the ...
Page 26
... common segment . For if it be possible let the straight lines GHK , GHL have a segment GH common to them . M G H L K From H draw HM at right angles to GH . Then because KHG is a straight line , therefore the angle KHM is equal to the ...
... common segment . For if it be possible let the straight lines GHK , GHL have a segment GH common to them . M G H L K From H draw HM at right angles to GH . Then because KHG is a straight line , therefore the angle KHM is equal to the ...
Other editions - View all
Euclid, Book I., Propositions I. to XXVI., with Exercises and Alternative ... Euclides No preview available - 2016 |
Euclid, Book I., Propositions I. to Xxvi., With Exercises and Alternative ... Euclides No preview available - 2023 |
Euclid, Book I., Propositions I. to Xxvi., With Exercises and Alternative ... Euclides No preview available - 2023 |
Common terms and phrases
A'EF AB is equal AC is equal ACD is greater adjacent angles angle ABC angle ACB angle BAC angle BCD angle BDC greater angle contained angle DEF angle DFE angle EDF angle equal bisects the angle centre circumference constr DEF are equal Demonstration describe the circle draw a straight equal angles equal sides equal to CD equidistant equilateral triangle Euclid exterior angle Find a point four-sided figure given line given point given straight line greater than BC interior opposite angle intersect isosceles triangle less Let ABC line with BC middle point opposite sides perpendiculars let fall point G position be named produced prop PROPOSITION Q.E.D. Exercises quadrilateral right angles shew shewn side AC sides equal straight line drawn take any point THEOREM third side triangle ABC triangle DEF triangles be equal unequal vertical angle
Popular passages
Page 39 - IF two triangles have two sides of the one equal to two sides of the...
Page 25 - To draw a straight line at right angles to a given straight line, from a given point in the same.
Page 4 - When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the straight line which stands on the other is called a perpendicular to it.
Page 7 - If a straight line meet two straight lines, so as to make the two interior angles on the same side of it taken together less than two right angles...
Page 7 - Notions 1. Things which are equal to the same thing are also equal to one another. 2. If equals be added to equals, the wholes are equal. 3. If equals be subtracted from equals, the remainders are equal. 4. Things which coincide with one another are equal to one another.
Page 36 - 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.
Page 37 - ... shall be equal to three given straight lines, but any two whatever of these must be greater than the third.
Page 18 - Upon the same base, and on the same side of it, there cannot be two triangles that have their sides which are terminated in one extremity of' the base, equal to one another, and likewise those which are terminated in the other extremity.
Page 29 - If, at a point in a straight line, two other straight lines, upon the opposite sides of it, make the adjacent angles together equal to two right angles, these two straight lines shall be in one and the same straight line. At the point B in the straight line AB, let the two straight lines...
Page 3 - A plane rectilineal angle is the inclination of two straight lines to one another, which meet together, but are not in the same straight line.