There's Something About Triangles
Scottish Country Dance Instruction
THERE'S SOMETHING ABOUT TRIANGLES (R3x32) 3C Triangular Set Holly Boyd Oh, How We've Danced!1- 2 All set, Ladies set advancing pulling back RSh to end BtoB in centre facing out between partner and corner
3- 8 All set as in Double Triangles, all set advancing pulling back RSh to invert triangle and set (Men now in centre BtoB facing out)
9-12 Men turn Lady to right RH
13-16 Men change places LH with partner and Men leading, followed by partner, chase anticlockwise 1 place
17-24 All join hands with partner (Lady on Man's left) and advance and retire; All set and link
25-32 All advance and retire; all set and Petronella in Tandem 1 place anticlockwise
(MINICRIB. Dance crib compiled by Charles Upton, Deeside Caledonian Society, and his successors)
Dance Information
There really is something about triangles.Far from being just another geometric shape, triangles possess several unique properties that have found applications in fields ranging from surveying and navigation to architecture and engineering.
Apart from being a polygon with three corners and three sides...
- A triangle is the only polygon that cannot be deformed without changing the length of one of its sides. A square made from rigid rods can collapse into a rhombus, but a triangle remains rigid. For this reason, triangles are widely used in bridges, roof trusses, cranes, electricity pylons and other structures.
- Any three non-collinear points define exactly one triangle. The same is not true of polygons with more sides, which require additional information to determine their shape.
- The interior angles of a triangle add up to 180 degrees in ordinary Euclidean geometry. On curved surfaces the total can differ. On a sphere, such as the Earth, a triangle can have three right angles and an angle sum greater than 180 degrees.
- The ancient Egyptians used a rope marked into twelve equal sections to create a 3-4-5 right-angled triangle for surveying and construction work.
- A triangle has the fewest sides possible for a polygon. Two straight line segments cannot enclose an area.
- The simplest stable space frame is a tetrahedron, which consists of four triangular faces. Many engineering structures and geodesic domes are based on this principle.
"Triangles", Edward Wadsworth (1889–1949) Tempera Painting, c. 1948
This page uses content under the Creative Commons Attribution-ShareAlike 4.0 International License, along with original copyrighted content and excerpts from Wikipedia and other sources.
Text from this original Triangle article on Wikipedia.
Image from Edward Wadsworth, Public domain, via Wikimedia Commons.
