## Elementary and Constructional Geometry |

### From inside the book

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**anti- parallel**. Parallel lines that have the same direction are called symparallel lines , and those that have exactly opposite directions are called**antiparallel**lines . Thus ,**antiparallel**lines form an angle of 180 ° with each other ... Page 22

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**antiparallel**lines . Thus A B ↑ ↓ DC means that A B runs in the opposite direction to D C , or A B is**antiparallel**to D C. If single letters are used , the direction of the lines is not indicated ; so that the sign without the arrow ... Page 31

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**antiparallel**or symparallel to A B ? 165. Repeat the problem of 164 three times , placing A , B , and C in different positions each time . 166. The last four exercises lead to the following prin- ciple : If two lines are crossed by a ... Page 56

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**antiparallel**. It is possible to fix the value of the value of A. Do you see how ? If what is D ? If / B = 25 ° , what is C ? help you to find / C ? Does A 288. If , in making a trapezoid A B C D , you first make [ A = 70 ° and B = 40 ... Page 81

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**antiparallel**to D B , where would you have stopped the movement ? Illustrate with a figure , using the same quadrilateral as in 406 . 408. Draw the diagonal C A , Fig . 62 , and mould the quadrilateral into a triangle in two ways ...### Other editions - View all

### Common terms and phrases

A B C D altitude angle formed angles alike angles equal answer antiparallel base angle bisect called centre chord circle circumference Compare compasses construction corresponding diagonal diameter direction distance dividing tool Draw a line edges equal triangles equivalent figure Find a square Geometry give hexagon hypotenuse Imagine inch inscribed angle isosceles triangle legs length line A B M N P measure method middle point mould move number of degrees oblique pair paper parallel parallelogram pentagon perpendicular piece plane polygon position principle protractor prove quadrilateral radius rectangle rectangular parallelopiped represented rhomboid rhombus right angles right triangle ruler scalene triangle scholium semicircumference shape similar triangles solid square form straight angle straight line strip surface symparallel tangent three lines trapezium trapezoid triangle A B C triangular prism triangular pyramid unequal vertex vertices width

### Popular passages

Page 111 - A circle is a plane figure bounded by a curved line, called the circumference, every point of which is equally distant from a point within called the center.

Page 66 - The straight line drawn through the mid-point of one side of a triangle parallel to the base bisects the other side.

Page 55 - Two triangles are congruent if the three sides of one are equal to the three sides of the other. Fig.

Page 49 - Two triangles are congruent if (a) two sides and the included angle of one are equal, respectively, to two sides and the included angle of the other...

Page 91 - The square described on the hypotenuse of a right triangle is equivalent to the sum of the squares on the other two sides.

Page 100 - The square root of a number is one of the two equal factors of the number.

Page 115 - In general, any rectilinear figure, as ABC, is said to be inscribed in a circle, when its angular points are on the circumference; and the circle is then said to be circumscribed about the figure. An angle is said to be inscribed in a segment when its vertex is in the arc of the segment, and its sides pass through the extremities of the subtending chord. Thus, the angle BA C is inscribed in the segment BAC.

Page 86 - ABCD tends to become a parallelogram, having a base equal to ^ the circumference and an altitude equal to the radius.

Page 44 - If two lines form a right angle, they are said to be perpendicular to each other ; if they form any other angle, they are said to be oblique to each other. Abbreviation : The sign _L means