The Elements of Euclid, books i. to vi., with deductions, appendices and historical notes, by J.S. Mackay. [With] Key1884 |
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Page 35
... into 4 equal parts . 8. Could the number of equal parts into which a straight line may be divided be extended beyond 4 ? If so , enumerate the numbers . 9. Find a straight line half as long again as Book I. ] 35 PROPOSITIONS 9 , 10 .
... into 4 equal parts . 8. Could the number of equal parts into which a straight line may be divided be extended beyond 4 ? If so , enumerate the numbers . 9. Find a straight line half as long again as Book I. ] 35 PROPOSITIONS 9 , 10 .
Page 36
... half the sum of two given straight lines . 11. Find a straight line equal to half the difference of two given straight lines . 12. If , in the figure to the proposition , A is bisected by AF , which meets BC at F , prove BF = BD , and ...
... half the sum of two given straight lines . 11. Find a straight line equal to half the difference of two given straight lines . 12. If , in the figure to the proposition , A is bisected by AF , which meets BC at F , prove BF = BD , and ...
Page 37
... half of a right angle . 4. At a given point in a given straight line make an angle equal to one - fourth of a right angle . 5. Construct an isosceles right - angled triangle . 6. Construct a right - angled triangle whose base shall be ...
... half of a right angle . 4. At a given point in a given straight line make an angle equal to one - fourth of a right angle . 5. Construct an isosceles right - angled triangle . 6. Construct a right - angled triangle whose base shall be ...
Page 71
... half a right angle . 2. If two isosceles triangles have their vertical angles equal , they are mutually equiangular . 3. If one angle of a triangle be equal to the sum of the other two , it must be right . 4. If one angle of a triangle ...
... half a right angle . 2. If two isosceles triangles have their vertical angles equal , they are mutually equiangular . 3. If one angle of a triangle be equal to the sum of the other two , it must be right . 4. If one angle of a triangle ...
Page 72
... half the exterior vertical angle . 14. If the exterior vertical angle of an isosceles triangle be bisected , the bisector is || the base . ။ 15. Show that the space round a point can be filled up with six equilateral triangles , or ...
... half the exterior vertical angle . 14. If the exterior vertical angle of an isosceles triangle be bisected , the bisector is || the base . ။ 15. Show that the space round a point can be filled up with six equilateral triangles , or ...
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Common terms and phrases
AB² ABCD AC² AD² angles equal base BC bisected bisector CD² centre chord circumscribed Const deduction diagonals diameter divided in medial divided internally draw equiangular equilateral triangle equimultiples Euclid's exterior angles Find the locus given circle given point given straight line greater Hence hypotenuse inscribed intersection isosceles triangle less Let ABC lines is equal magnitudes medial section median meet middle points opposite sides orthocentre parallel parallelogram perpendicular polygon produced PROPOSITION 13 Prove the proposition quadrilateral radical axis radii radius ratio rectangle contained rectilineal figure regular pentagon required to prove rhombus right angle right-angled triangle square on half straight line drawn straight line joining tangent THEOREM unequal segments vertex vertical angle Нур
Popular passages
Page 147 - 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 276 - IF there be any number of magnitudes, and as many others, which, taken two and two, in a cross order, have the same ratio; the first shall have to the last of the first magnitudes the same ratio which the first of the others has to the last. NB This is usually cited by the words
Page 331 - If the vertical angle of a triangle be bisected by a straight line which also cuts the base, the segments of the base shall have the same ratio which the other sides of the triangle have to one another...
Page 17 - From the greater of two given straight lines to cut off a part equal to the less. Let AB and C be the two given straight lines, whereof AB is the greater.
Page 112 - If a straight line be divided into any two parts, the rectangle contained by the whole and one of the parts, is equal to the rectangle contained by the two parts, together with the square of the aforesaid part.
Page 87 - Guido, with a burnt stick in his hand, demonstrating on the smooth paving-stones of the path, that the square on the hypotenuse of a right-angled triangle is equal to the sum of the squares on the other two sides.
Page 254 - If there be four magnitudes, and if any equimultiples whatsoever be taken of the first and third, and any equimultiples whatsoever of the second and fourth, and if, according as the multiple of the first is greater than the multiple of the second, equal to it or less, the multiple of the third is also greater than the multiple of the fourth, equal to it or less ; then, the first of the magnitudes is said to have to the second the same ratio that the third has to the fourth.
Page 138 - RULE. from half the sum of the three sides, subtract each side separately; multiply the half sum and the three remainders together, and the square root of the product will be the area required.
Page 304 - 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 44 - America, but know that we are alive, that two and two make four, and that the sum of any two sides of a triangle is greater than the third side.