Delta Curve

A curve which can be turned continuously inside an Equilateral Triangle. There are an infinite number of deltacurves, but the simplest are the Circle and lens-shaped -biangle. All the curves of height havethe same Perimeter . Also, at each position of a curve turning in an Equilateral Triangle,the perpendiculars to the sides at the points of contact are Concurrent at the instantaneous center of rotation.

References

Honsberger, R. Mathematical Gems I. Washington, DC: Math. Assoc. Amer., pp. 56-59, 1973.

• Dimensionality Theorem
• Dimension Axiom
• Dimension Invariance Theorem
• Diminished Polyhedron
• Diminished Rhombicosidodecahedron
• Dini Expansion
• Dini's Surface
• Dini's Test
• Dinitz Problem
• Diocles's Cissoid
• Diophantine Equation
• Diophantine Equation--10th Powers
• Diophantine Equation--5th Powers
• Diophantine Equation--6th Powers
• Diophantine Equation--7th Powers
• Diophantine Equation--8th Powers
• Diophantine Equation--9th Powers
• Diophantine Equation--Cubic
• Diophantine Equation--Linear
• Diophantine Equation nth Powers
• Diophantine Equation--Quadratic
• Diophantine Equation--Quartic
• Diophantine Quadruple
• Diophantine Set
• Diophantus Property