## Elements of Geometry and Trigonometry |

### From inside the book

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**quadrilateral**ABCD is a parallelogram . PROPOSITION XXX . THEOREM . If two opposite sides of a**quadrilateral**are equal and parallel , the remaining sides will also be equal and parallel , and the figure will be a parallelogram . Let ... Page 55

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**quadrilateral**ABCD , are to- gether equal to two right angles : for the an- gle BAD is measured by half the arc BCD , the angle BCD is measured by half the arc BAD ; hence the two angles BAD , BCD , ta- D ken together , are measured by ... Page 69

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**quadrilateral**ABED , we take away the tri- angle ADF , there will remain the parallelogram ABEF ; and if from the same**quadrilateral**ABED , we take away the equal triangle CBE , there will remain the parallelogram ABCD . Hence these two ... Page 85

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**quadrilaterals**, the proportion between the sides may be altered without altering the angles , or the angles may be altered without altering the proportion between the sides ; and thus proportionality among the sides cannot be a ... Page 86

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**quadrilateral**AEFD , are made equal to those of ABCD , though the proportion be- tween the sides is different ; and , in like man- ner , without changing the four sides AB , BC , CD , AD , we can make the point B approach D or recede ...### Other editions - View all

### Common terms and phrases

adjacent adjacent angles altitude angle ACB angle BAC ar.-comp base multiplied bisect Book centre chord circ circumference circumscribed common cone consequently convex surface cylinder diagonal diameter dicular distance draw drawn equal angles equally distant equation equiangular equivalent figure formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed circle inscribed polygon intersection less Let ABC let fall logarithm measured by half number of sides opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular plane MN polyedron polygon ABCDE prism proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABC Scholium secant secant line segment side BC similar solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex