An Elementary Treatise on Plane and Solid Geometry |
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Page 72
... product of its base by its altitude . 248. Corollary . Parallelograms of the same base are to each other as their altitudes ; and those of the same altitude are to each other as their bases . 249. Problem . Every triangle is half of a ...
... product of its base by its altitude . 248. Corollary . Parallelograms of the same base are to each other as their altitudes ; and those of the same altitude are to each other as their bases . 249. Problem . Every triangle is half of a ...
Page 73
... half the product of its altitude by the sum of its parallel sides . Proof . Draw the diagonal AD ( fig . 129 ) ; the trape- zoid ABCD is divided into two triangles ACD and ABD , the bases of which are AB and CD , and the altitude of ...
... half the product of its altitude by the sum of its parallel sides . Proof . Draw the diagonal AD ( fig . 129 ) ; the trape- zoid ABCD is divided into two triangles ACD and ABD , the bases of which are AB and CD , and the altitude of ...
Page 80
... half the product of its perimeter by the radius of the inscribed circle . Proof . From the centre O ( fig . 134 ) of the circle draw Area of a Circle . OA , OB , OC 80 PLANE GEOMETRY . [ CH . XIII . § 277 .
... half the product of its perimeter by the radius of the inscribed circle . Proof . From the centre O ( fig . 134 ) of the circle draw Area of a Circle . OA , OB , OC 80 PLANE GEOMETRY . [ CH . XIII . § 277 .
Page 81
... half the product of its base AB , BC , CD , & c . by the common altitude OM . The sum of the areas of the triangles , or the area of the polygon is , consequently , half the product of the sum of the sides , AB , BC , & c . by the ...
... half the product of its base AB , BC , CD , & c . by the common altitude OM . The sum of the areas of the triangles , or the area of the polygon is , consequently , half the product of the sum of the sides , AB , BC , & c . by the ...
Page 82
... half the product of its arc by its radius . Proof . Suppose the arc AB ( fig . 135 ) of the sector AOB divided into ... half the product of the sum of the bases AM , MN , NP , & c . by the common altitude OA ; that is , half the product ...
... half the product of its arc by its radius . Proof . Suppose the arc AB ( fig . 135 ) of the sector AOB divided into ... half the product of the sum of the bases AM , MN , NP , & c . by the common altitude OA ; that is , half the product ...
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Common terms and phrases
ABC fig adjacent angles angle BAC arc BC base and altitude bisect centre chord circumference common altitude construct convex surface Corollary DEF fig Definitions denote diameter divided Draw equal arcs equal distances equiangular with respect equilateral equivalent frustum given angle given circle given line given polygon given sides given square gles greater half the product Hence homologous sides hypothenuse infinite number infinitely small Inscribed Angle inscribed circle isosceles Let ABCD line AB fig line BC lines drawn mean proportional number of sides oblique lines parallel lines parallel to BC parallelogram parallelopipeds perimeter perpendicular plane MN polyedron polygon ABCD &c Problem Proof pyramid or cone radii radius rectangles regular polygon right triangle Scholium sector segment side BC similar polygons similar triangles solid angle Solution sphere spherical polygon spherical triangle straight line tangent Theorem triangles ABC triangular prism vertex vertices whence
Popular passages
Page 68 - The perimeters of two regular polygons of the same number of sides, are to each other as their homologous sides, and their areas are to each other as the squares of those sides (Prop.
Page 127 - Every section of a sphere, made by a plane, is a circle, Let AMB be a section, made by a plane, in the sphere whose centre is C.
Page 71 - Rectangles of the same altitude are to each other as their bases, and rectangles of the same base are to each other as their altitudes. 245.
Page 20 - The sum of the three angles of any triangle is equal to two right angles.
Page xv - The first term of a ratio is called the antecedent, and the second term the consequent.
Page 83 - ... we suppose the error A to be of any magnitude whatever. 286. Definition. Similar sectors and similar segments are such as correspond to similar arcs. 287. Theorem. Similar sectors are to each other as the squares of their radii. Proof. The similar sectors AOB, A'OB ' (fig. 136) are, by the same reasoning as in t5 97, the same parts of their respective circles, which the angle O= O...
Page 31 - Theorem. In the same circle, or in equal circles, equal arcs are subtended by equal chords.
Page 87 - To construct a parallelogram equivalent to a given square, and having the sum of its base and altitude equal to a given line.
Page 99 - B, from the plane. 320. Theorem. Oblique lines drawn from a point to a plane at equal distances from the perpendicular are equal; and of two oblique lines unequally distant the more remote is the greater.
Page 78 - Similar triangles are to each other as the squares of their homologous sides. Proof. In the similar .triangles ABC, A'B'C