 | Hippolyte Taine - 1998 - 588 sider
...together equal to four right angles ; hence it follows that the polygon contains a number of angles which, together with four right angles, are equal to twice as many right angles as there are sides. — Here the explanatory intermediate is a character comprised in all the elements... | |
 | ...regular decagon. The corollary to Euc. i. 32 states that all the interior angles of any rectilinear figure together with four right angles are equal to twice as many right angles as the figure has sides. Let the angle of a regular decagon contain x right angles, so that all the angles are together... | |
 | 1891
...an application of Euclid I. 82, Cor. 1, which proves that 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. To be able to apply this test, one must first find out the interior angles from the bearings.... | |
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F, which is the common vertex of the triangles ; that is, together with four right angles. Therefore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. 
