... polygon, is equal to twice as many right angles as the polygon has sides minus two. An Elementary Geometry - Page 20 by William Frothingham Bradbury - 1872 - 110 pages Full view - About this book
...sides ; [i. 32] therefore the interior angles of the polygon together with all the angles round O are equal to twice as many right angles as the polygon has sides. Also the sum of the angles of the triangles VAB, VBC, etc., with vertex Fare equal to twice as many...
... polygon, is equal to twice as many right angles as the polygon has sides minus two. 
