Relo Triangle Calculator

The Reulot triangle is the area of intersection of three equal circles with centers at the vertices of a regular triangle and radii equal to its side. The non-smooth closed curve bounding this figure is also called the Reulot triangle. This is the simplest form of a constant width curve. Its two-dimensional equivalent is the Reulot tetrahedron. Enter one known value, then click the “Calculate” button.


Relo Triangle Calculator

Radius, side length (a)
Arc length (l)
Perimeter (P)
Square (S)


l = a π / 3
p = a π
S = ( π – √3 ) a2 / 2