## Elements of Geometry and Trigonometry |

### From inside the book

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**perpendicular**to CD . 11. Every angle BAC , less than a right angle , is an acute angle ; and every angle DEF , greater than a right angle , is an obtuse angle . E 12. Two lines are said to be parallel , when being situated in the same ... Page 14

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**perpendicular**to AB , reciprocally , AB will be perpendicu- lar to DE . For , since DE is**perpendicular**to AB , the angle ACD must be equal to its adjacent an- gle DCB , and both of them must be right angles ( Def . 10. ) . But since ... Page 20

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**perpendicular**to the base , and divides the angle at the vertex into two equal parts . In a triangle which is not isosceles , any side may be assumed indifferently as the base ; and the vertex is , in that case , the vertex of the ... Page 22

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**perpendicular**be let fall on the line , and oblique lines be drawn to different points : 1st , The**perpendicular**will be shorter than any oblique line . 2d , Any two oblique lines , drawn on different sides of the perpen- dicular ... Page 23

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**perpendicular**, and AD , AC , AE , the oblique lines . Produce the**perpendicular**AB till BF is equal to AB , and draw FC , FD . First . The triangle BCF , is equal to the triangle BCA , for they have the right angle CBF CBA , the side ...### 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 convex surface Cosine Cotang cylinder diagonal diameter dicular distance draw drawn equal angles equally distant equiangular equivalent figure formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed polygon intersection less Let ABC let fall logarithm measured by half number of sides oblique lines 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 sine solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex