Elements of geometry for the use of schools (1854)
Ireland. Board of National Education · Dublin : A. Thom · leaf 27
gle D C F, and taking ^2°nfrom the whole figure the triangle ABE. arobJtwLnBut since the two triangles D CF, ABE. raS^aie*are supposed to be equal, it is evident that the cquaparallelogram ABCD is not altered in di-mensions by becoming EBCF. Now to becertain that these triangles are equal, we… … 18 ELEMENTS OF GEOMETRY. XX. There are still other rectilineal figureswhose measurement is easy, and which arecalled regular Polygons, or figures termi-nated by equal sides, with the same mutualSuch are the figures ABDEF, T?o;jular po-lygons aroreotiUneal tieurea tcr-minatoti bysides allequal…
Geometry
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![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-127-351.webp)