## Elements of Geometry and Trigonometry |

### From inside the book

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**quadrilateral**; that of five , a pentagon ; that of six , a hexagon ; that of seven , a heptagon ; that of eight , an octagon ; that of nine , a nonagon ; that of ten , a decagon ; and that of twelve , a dodecagon . C 15. An equilateral ... Page 11

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**quadrilaterals**, we distinguish : The square , which has its sides equal , and its an- gles right - angles . The rectangle , which has its angles right an- gles , without having its sides equal . The parallelogram , or rhomboid , which ... Page 30

... in the number of sides diminished by two . Cor . 1. The sum of the angles in a

... in the number of sides diminished by two . Cor . 1. The sum of the angles in a

**quadrilateral**is equal to two right angles multiplied by 4-2 , which amounts to four right angles : hence , if all the angles of. 30 GEOMETRY . Page 31

Adrien Marie Legendre. right angles : hence , if all the angles of a

Adrien Marie Legendre. right angles : hence , if all the angles of a

**quadrilateral**are equal , each of them will be a right angle ; a conclusion which sanctions the seventeenth Definition , where the four angles of a**quadrilateral**are ... Page 32

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**quadrilateral**are equal , each to each , the equal sides will be parallel , and the figure will be a par- allelogram . Let ABCD be a**quadrilateral**, having its opposite sides respectively equal , viz . AB DC , and AD = BC ; then will ...### Other editions - View all

### Common terms and phrases

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