Quandaries
and Queries 

I am trying to remember the name given to the regular figure constructed from three arcs. The figure is like an equilateral triangle except with arcs for each side. Can you help? Bob 

Hi Bob, If each arc is a piece of a circle whose center is one vertex and whose radius equals the length of a side, the triangle is called a Reuleaux triangle (named after Franz Reuleaux, a French engineer). See http://mathworld.wolfram.com/ReuleauxTriangle.html for more information. In general, a figure in the plane with three curved sides is called a curvilinear triangle. Chris 

