Linked from

The 76 pages that link to Circle, each with the reason it gives.

• RadianRelated: Its radius and circumference define how radians measure an angle.

• Centripetal forceRelated: Its radius and center define the geometry used to describe centripetal force.

• Angular frequencyRelated: One full revolution supplies the 2π-radian phase change per cycle.

• HomeomorphismRelated: A circle and the boundary of a square are homeomorphic despite their different outlines.

• Surface areaRelated: Circular regions form the ends of cylinders and contribute to their surface area.

• MidpointRelated: The midpoint of a diameter is the circle’s center.

• Möbius transformationRelated: Möbius maps carry generalized circles, including lines, to generalized circles.

• PerimeterRelated: Its boundary length is called circumference, the circular counterpart of perimeter.

• Cross-ratioRelated: A Möbius transformation maps generalized circles to generalized circles, allowing cross-ratios to test cyclic configurations.

• Polar coordinate systemRelated: A circle centered at the origin is specified by a constant radius.

• MandalaRelated: Circular boundaries often mark the mandala's sacred enclosure.

• Thales' theoremRelated: The circle supplies the arc on which the right angle's vertex lies.

• PendentiveRelated: The dome’s circular base meets the curved surfaces above the square bay.

• TorusRelated: The torus is formed as the product of two circles.

• Brahmagupta's formulaRelated: A cyclic quadrilateral is defined by its vertices lying on one circle.

• Distance formulaRelated: The distance formula tests whether a point lies at a circle’s radius from its center.

• Homotopy equivalenceRelated: It represents the homotopy type of the punctured plane and many annular spaces.

• Stereographic projectionRelated: Circles on the sphere project to circles or straight lines in the plane.

• Intersecting chords theoremRelated: The chord endpoints lie on this curve, which supplies the proof’s angle relations.

• ConeRelated: The cone’s base is circular, and its radius determines the base’s size.

• Hippocrates of ChiosRelated: His construction uses relationships among arcs and areas of circles.

• Surface of revolutionRelated: Rotating a circle in its plane around a coplanar axis produces familiar toroidal or spherical cases.

• Vitruvian ManRelated: The outstretched limbs fit a circular boundary in Leonardo's construction.

• Barbier's theoremRelated: Its circumference is 2πr, exactly π times its width 2r.

• Inversive geometryRelated: The circle of inversion determines the reciprocal distances and remains pointwise fixed.

• Poncelet–Steiner theoremRelated: Its fixed boundary provides the metric reference absent from a bare straightedge.

• Proof that π is irrationalRelated: The circumference-to-diameter ratio defining π comes from circle geometry.