Elements of Geometry and Trigonometry from the Works of A.M. Legendre: Adapted to the Course of Mathematical Instruction in the United States |
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Page vii
... Parallelogram , 118 The Area of a Triangle , ...... 118 Formula for the Sine and Cosine of Half an Angle , 120 Area of a Trapezoid , 125 Area of a Quadrilateral , 126 Area of a Polygon , 126 Area of a Regular Polygon ,. 127 To find the ...
... Parallelogram , 118 The Area of a Triangle , ...... 118 Formula for the Sine and Cosine of Half an Angle , 120 Area of a Trapezoid , 125 Area of a Quadrilateral , 126 Area of a Polygon , 126 Area of a Regular Polygon ,. 127 To find the ...
Page 17
... PARALLELOGRAM is a quadrilateral which has its opposite sides parallel , two and two . There are and rhomboids . two varieties of parallelograms : rectangles 1st . A RECTANGLE is a parallelogram whose angles are all right angles . A ...
... PARALLELOGRAM is a quadrilateral which has its opposite sides parallel , two and two . There are and rhomboids . two varieties of parallelograms : rectangles 1st . A RECTANGLE is a parallelogram whose angles are all right angles . A ...
Page 43
... HMB is equal to its alternate angle MBC ( P. XX . , C. 2 ) : hence , GHK is equal to ABC ; which was to be proved . Cor . The opposite angles of a parallelogram are equal . PROPOSITION XXV . THEOREM . In any triangle , the BOOK I. 43.
... HMB is equal to its alternate angle MBC ( P. XX . , C. 2 ) : hence , GHK is equal to ABC ; which was to be proved . Cor . The opposite angles of a parallelogram are equal . PROPOSITION XXV . THEOREM . In any triangle , the BOOK I. 43.
Page 47
... parallelogram , the opposite sides are equal , each to each . Let ABCD be a parallelogram : then AB is equal to DC , and AD to BC . parallel , the its alternate D B For , draw the diagonal BD . Then , because AB and DC are angle DBA is ...
... parallelogram , the opposite sides are equal , each to each . Let ABCD be a parallelogram : then AB is equal to DC , and AD to BC . parallel , the its alternate D B For , draw the diagonal BD . Then , because AB and DC are angle DBA is ...
Page 48
... parallelogram . In the quadrilateral ABCD , let AB be equal to DC , and AD to BC : then is it a parallelogram . D A B Draw the diagonal DB . Then , the triangles ADB and CBD , have the sides of the one equal to the sides of the other ...
... parallelogram . In the quadrilateral ABCD , let AB be equal to DC , and AD to BC : then is it a parallelogram . D A B Draw the diagonal DB . Then , the triangles ADB and CBD , have the sides of the one equal to the sides of the other ...
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Common terms and phrases
ABCD AC² adjacent angles altitude apothem Applying logarithms bisects centre chord circle circumference circumscribed cone consequently convex surface cosec cosine Cotang cylinder denote diagonals diameter difference distance divided draw drawn edges equilateral feet find the area formula frustum given angle given line given point greater hence homologous hypothenuse included angle inscribed intersection isosceles less Let ABC log sin lower base lune mantissa number of sides parallel parallelogram parallelopipedon perimeter perpendicular plane angles plane MN polyedral angle polyedron principle demonstrated prism PROBLEM.-In PROPOSITION proved pyramid quadrant radii radius rectangle regular polygon right angles right-angled triangle Scholium secant segment semi-circumference similar sine slant height solution sphere spherical angle spherical polygon spherical triangle square straight line subtracting supplement Tang tangent THEOREM THEOREM.-Show tri-rectangular triangle ABC triangular prism triedral angle upper base vertex vertices volume whence
Popular passages
Page 28 - If two triangles have two sides of the one equal to two sides of the...
Page 90 - A cos 6 = cos a cos c + sin a sin c cos B cos c = cos a cos 6 + sin a sin 6 cos C Law of Cosines for Angles cos A = — cos B...
Page 18 - Things which are equal to the same thing, are equal to each other. 2. If equals are added to equals, the sums are equal. 3. If equals are subtracted from equals, the remainders are equal. 4. If equals are added to unequals, the sums are unequal.
Page 4 - The logarithm of any power of a number is equal to the logarithm of the number multiplied by the exponent of the power.
Page 253 - For, the point A being the pole of the arc EF, the distance AE is a 'quadrant ; the point C being the pole of the arc DE, the distance CE is likewise a quadrant : hence the point E is...
Page 61 - A Circle is a plane figure bounded by a curved line every point of which is equally distant from a point within called the center.
Page 94 - A'B'C', and applying the law of cosines, we have cos a' = cos b' cos c' + sin b' sin c' cos A'. Remembering the relations a' = 180° -A, b' = 180° - B, etc. (this expression becomes cos A = — cos B cos C + sin B sin C cos a.
Page 126 - If two polygons are composed of the same number of triangles, similar each to each and similarly placed, the polygons are similar.
Page 46 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 125 - THEOREM. Similar triangles are to each other as the squares of their homologous sides.