Related Terms: Arc, Epicycloid, Sector, Circumference, Major arc, Semicircle, Circular, Radius, Spherical triangle, Radius of curvature, Concentric circles, Cycloid, Tangent to a circle, Circle, Geodesic, Torus, Tangent, Conic section, Spiral, Kreisel, Tangent plane, Secant, Chord of a circle, Diameter, Ellipse, Chord , Radian, Hyperbola, Involute, Envelope, Inscribed angle, Great circle route, Parabola , Sphere, Cylinder, Saddle point, Concentric, Curvature, Cep, Ruled surface, Radius, Ring, Solid angle, Central angle, Cone , Directrix, Great circle, Curve, Center circle, Circular error probable