“Straight edges and compasses work fine for the recurring symmetries of the simplest patterns we see, but it probably required far more powerful tools to fully explain the elaborate tiling with decagonal 10-sided symmetry,” Mr Lu said.    From Wordnik.com.  [Archive 2007-02-01] Reference

It was decagonal in plan, with a projecting buttress at each angle.    From Wordnik.com.  [Bell’s Cathedrals: The Cathedral Church of Hereford, A Description Of Its Fabric And A Brief History Of The Episcopal See] Reference

The upper story is also decagonal, and is reached by a flight of modern stone steps.    From Wordnik.com.  [The Complete Project Gutenberg Writings of Charles Dudley Warner] Reference

The earliest example is probably that of Lincoln, decagonal in shape, which was built from 1240-1260.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 3: Brownson-Clairvaux] Reference

The mausoleum of Theodoric, a decagonal structure, covered with a great monolith thirty-six feet in diameter, is the monument that reveals Roman art in its purest form, at once austere and graceful.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 12: Philip II-Reuss] Reference

Medieval Islamic Architecture Presages 20th-century Mathematics Intricate decorative tilework found in medieval architecture across the Islamic world appears to exhibit advanced decagonal quasicrystal geometry -- a concept discovered by Western mathematicians and physicists only in the 1970s and 1980s.    From Wordnik.com.  [Clipmarks | Live Clips] Reference

∗ n 2n − 0 n 3n − 1 n 4n − 2 n 2 2 = n2 2 2 Based on the pattern developing across the nth row, have your students determine what the general forms of the heptagonal, octagonal, decagonal, etc., numbers are.    From Wordnik.com.  [Recently Uploaded Slideshows] Reference

5576 is a decagonal pyramidal number. idempotents.    From Wordnik.com.  [Netvouz - new bookmarks] Reference

(4) Theodoric died in 526 A.D. His mausoleum is formed by a polygon of ten equal sides, with a smaller decagonal upper stage, a circular attic above which bears the great monolithic dome.    From Wordnik.com.  [The Ground Plan of the English Parish Church] Reference

1375 is a decagonal pyramidal number.    From Wordnik.com.  [Netvouz - new bookmarks] Reference

9310 is a decagonal pyramidal number. prime.    From Wordnik.com.  [Netvouz - new bookmarks] Reference