An Introduction to Geometry and the Science of Form: Prepared from the Most Approved Prussian Text-books |
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Page 34
... angles ; for BAD is a right angle ; therefore DAF must be a right angle ; since by the definition of a right angle ... concave angles . Obtuse , right , and acute angles are all concave angles . Wherever there is a concave angle ...
... angles ; for BAD is a right angle ; therefore DAF must be a right angle ; since by the definition of a right angle ... concave angles . Obtuse , right , and acute angles are all concave angles . Wherever there is a concave angle ...
Page 35
... angles , viz .: 1 convex and 1 concave . Three straight lines may form 6 angles , viz .: 3 convex and 3 concave . The whole number of angles formed at a point is double the number of the concave angles . For as there is a convex ...
... angles , viz .: 1 convex and 1 concave . Three straight lines may form 6 angles , viz .: 3 convex and 3 concave . The whole number of angles formed at a point is double the number of the concave angles . For as there is a convex ...
Page 36
... angles , one will be a concave angle less than 2 R. A .; the other a convex angle greater than 2 R. A. As much as ... angles . There may be 3 concave , or 2 concave and 1 convex . If the 3 concave angles are equal , each is an ...
... angles , one will be a concave angle less than 2 R. A .; the other a convex angle greater than 2 R. A. As much as ... angles . There may be 3 concave , or 2 concave and 1 convex . If the 3 concave angles are equal , each is an ...
Page 37
... angles which a rectilineal figure may have ? A convex angle , when it occurs in a figure , is called a re - entering angle , because the vertex is directed in- wards ; the concave angles are called salient angles . In all the rules and ...
... angles which a rectilineal figure may have ? A convex angle , when it occurs in a figure , is called a re - entering angle , because the vertex is directed in- wards ; the concave angles are called salient angles . In all the rules and ...
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Common terms and phrases
adjacent angles angle BAC angles are equal Bisect centre chord circumference coincide concave angles consequently angle construct a square convex angle convex surface cube curved line cylinder decagonal 66 describe a circle diagonals diameter divided division points draw a line Draw a straight equal altitude equal angles equal bases equivalent erect a perpendicular exterior angles feet find the number formed found by multiplying given number given square greatest number hexagon inches inscribed circle isosceles triangle length let fall line drawn line passes magnitude measured Multiply the number number of lines number of points number of straight opposite parallelogram parallelopiped passes 2 points pendicular perpendicular proportion protractor quadrilateral radii radius equal ratio regular polygon right angle semi-circumference set intersecting side AC Solid Angles solidity sphere straight line suppose tangents triangle ABC triangular prism unequal vertex vertices
Popular passages
Page 130 - The first and fourth terms of a proportion are called the extremes, and the second and third terms, the means. Thus, in the foregoing proportion, 8 and 3 are the extremes and 4 and 6 are the means.
Page 154 - In a series of equal ratios, any antecedent is to its consequent, as the sum of all the antecedents is to the sum of all the consequents. Let a: 6 = c: d = e :/. Then, by Art.