Elements of Geometry and Trigonometry: From the Works of A.M. Legendre |
From inside the book
Results 1-5 of 15
Page 160
... plane . For , let AB and CD ( B. I. , D. 16 ) two parallel lines always lie in the same plane . But either line , as ... MN be the plane of the two lines BB , CC , and let AP be perpendicular to these lines at P : then will AP be ...
... plane . For , let AB and CD ( B. I. , D. 16 ) two parallel lines always lie in the same plane . But either line , as ... MN be the plane of the two lines BB , CC , and let AP be perpendicular to these lines at P : then will AP be ...
Page 161
... plane which passes through P , and consequently , to the plane itself . For , through P , draw in the plane MN , any line PQ ; through any point of this line , as Q , draw the line BC , 80 that BQ shall be equal to QC ( B. IV . , Prob ...
... plane which passes through P , and consequently , to the plane itself . For , through P , draw in the plane MN , any line PQ ; through any point of this line , as Q , draw the line BC , 80 that BQ shall be equal to QC ( B. IV . , Prob ...
Page 162
... plane from a point of that plane . For , suppose that two perpen- diculars could be drawn to the plane MN , from the point P. Pass a plane through the perpendiculars , and let PQ be its intersection with MN ; then we should have two per ...
... plane from a point of that plane . For , suppose that two perpen- diculars could be drawn to the plane MN , from the point P. Pass a plane through the perpendiculars , and let PQ be its intersection with MN ; then we should have two per ...
Page 163
... plane MN in the circumference of a circle , whose centre is P , and whose radius is PB : hence , to draw a perpendi cular to a given plane MN , from a point A , without that plane , find three points B , C , D , of the plane equally dis ...
... plane MN in the circumference of a circle , whose centre is P , and whose radius is PB : hence , to draw a perpendi cular to a given plane MN , from a point A , without that plane , find three points B , C , D , of the plane equally dis ...
Page 164
... plane MN , Pits foot , BC the given line , and A any point of the perpendicular ; draw PD at right angles to BC , and join the point D with A then will AD be perpendicular to BC . For , lay of DB equal to DC , and draw PB , PC , AB ...
... plane MN , Pits foot , BC the given line , and A any point of the perpendicular ; draw PD at right angles to BC , and join the point D with A then will AD be perpendicular to BC . For , lay of DB equal to DC , and draw PB , PC , AB ...
Other editions - View all
Common terms and phrases
ABē ABCD ACē adjacent angles altitude apothem Applying logarithms base and altitude bisect centre chord circle circumference circumscribed coincide cone consequently convex surface corresponding cosec cosine Cotang cylinder denote diagonals diameter difference distance divided draw drawn edges equally distant feet find the area Formula frustum given angle given straight line greater hence homologous hypothenuse included angle interior angles intersection less Let ABC log sin lower base mantissa measured by half number of sides opposite parallel parallelogram parallelopipedon perimeter perpendicular plane MN polyedral angle polyedron prism PROPOSITION proved pyramid quadrant radii radius rectangle regular polygons right angles right-angled triangle Scholium secant segment semi-circumference side BC similar sine slant height sphere spherical polygon spherical triangle square subtracted Tang tangent THEOREM triangle ABC triangular prisms triedral angle upper base vertex vertices whence
Popular passages
Page 126 - The square of the hypothenuse is equal to the sum of the squares of the other two sides ; as, 5033 402+302.
Page 59 - 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 18 - The circumference of every circle is supposed to be divided into 360 equal parts called degrees, and each degree into 60 equal parts called minutes, and each minute into 60 equal parts called seconds, and these into thirds, fourths, &c.
Page 104 - The square described on the hypothenuse of a rightangled triangle is equal to the sum of the squares described on the other two sides.
Page 6 - The logarithm of any power of a number is equal to the logarithm of the number multiplied by the exponent of the power.
Page 28 - If two triangles have two sides of the one equal to two sides of the...
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 99 - The area of a parallelogram is equal to the product of its base and altitude.
Page 172 - If two planes are perpendicular to 'each other, a straight line drawn in one of them, perpendicular to their intersection, will be perpendicular to the other.
Page 214 - A sphere is a solid bounded by a curved surface, every point of which is equally distant from a point within called the center.