The most advanced part of plane Euclidean geometry is the theory of the conic sections (the ellipse, parabola, and hyperbola). Much as the Elements displaced all other introductions to geometry, the Conics of Apollonius of Perga (c. 240–190 bc), known by his contemporaries as “The Great Geometer,” was for many centuries the definitive treatise on the subject.
Medieval Islamic artists explored ways of using geometric figures for decoration. For example, the decorations of the Alhambra of Granada, Spain, demonstrate an understanding of all 17 of the different “Wallpaper groups” that can be used to tile the plane. In the 20th century, internationally renowned artists such as Josef Albers, Max Bill, and Sol Le Witt were inspired by motifs from Euclidean geometry.
The-figure-illustrates-the-three-basic-theorems-that-triangles-areThe figure illustrates the three basic theorems that triangles are congruent (of equal shape and …[Credits : Encyclopædia Britannica, Inc.]
Proof-that-the-sum-of-the-angles-in-a-triangleProof that the sum of the angles in a triangle is 180 degrees.[Credits : Encyclopædia Britannica, Inc.]
The-formula-in-the-figure-reads-k-is-to-lThe formula in the figure reads k is to l as m is to n if and only if …[Credits : Encyclopædia Britannica, Inc.]
[Credits : Encyclopædia Britannica, Inc.]
Thales-of-Miletus-is-generally-credited-with-giving-the-firstThales of Miletus (fl. c. 600 bc) is generally credited with giving the first proof that for any …[Credits : Encyclopædia Britannica, Inc.]
[Credits : Encyclopædia Britannica, Inc.]
Bridge-of-AssesBridge of Asses.[Credits : Encyclopædia Britannica, Inc.]
Quadrilateral-of-Omar-Khayyam-Omar-Khayyam-constructed-the-quadrilateral-shownQuadrilateral of Omar Khayyam[Credits : Encyclopædia Britannica, Inc.]
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